diff --git a/addons/hr_timesheet/models/project_task.py b/addons/hr_timesheet/models/project_task.py
index 15e2a5e229f..4479b766aac 100644
--- a/addons/hr_timesheet/models/project_task.py
+++ b/addons/hr_timesheet/models/project_task.py
@@ -7,7 +7,6 @@ from odoo.exceptions import UserError, RedirectWarning
 from odoo.addons.rating.models.rating_data import OPERATOR_MAPPING
 
 PROJECT_TASK_READABLE_FIELDS = {
-    'allow_subtasks',
     'allow_timesheets',
     'analytic_account_active',
     'effective_hours',
diff --git a/addons/hr_timesheet/views/hr_timesheet_views.xml b/addons/hr_timesheet/views/hr_timesheet_views.xml
index 6d80944bb43..5419a14179a 100644
--- a/addons/hr_timesheet/views/hr_timesheet_views.xml
+++ b/addons/hr_timesheet/views/hr_timesheet_views.xml
@@ -167,7 +167,7 @@
                     <field name="employee_id"/>
                     <field name="project_id"/>
                     <field name="task_id"/>
-                    <field name="parent_task_id" groups="project.group_subtask_project"/>
+                    <field name="parent_task_id"/>
                     <field name="name"/>
                     <field name="department_id"/>
                     <field name="manager_id"/>
@@ -176,7 +176,7 @@
                     <filter name="month" string="Date" date="date"/>
                     <group expand="0" string="Group By">
                         <filter string="Project" name="groupby_project" domain="[]" context="{'group_by': 'project_id'}"/>
-                        <filter string="Parent Task" name="groupby_parent_task" domain="[]" context="{'group_by': 'parent_task_id'}" groups="project.group_subtask_project"/>
+                        <filter string="Parent Task" name="groupby_parent_task" domain="[]" context="{'group_by': 'parent_task_id'}"/>
                         <filter string="Task" name="groupby_task" domain="[]" context="{'group_by': 'task_id'}"/>
                         <filter string="Date" name="groupby_date" domain="[]" context="{'group_by': 'date'}" help="Timesheet by Date"/>
                         <filter string="Department" name="groupby_department" domain="[]" context="{'group_by': 'department_id'}"/>
diff --git a/addons/hr_timesheet/views/project_task_sharing_views.xml b/addons/hr_timesheet/views/project_task_sharing_views.xml
index 2b590d785fd..a0ce37d1b15 100644
--- a/addons/hr_timesheet/views/project_task_sharing_views.xml
+++ b/addons/hr_timesheet/views/project_task_sharing_views.xml
@@ -20,8 +20,8 @@
                 <label for="planned_hours" attrs="{'invisible': [('allow_timesheets', '=', False)]}"/>
                 <div class="text-nowrap" attrs="{'invisible': [('allow_timesheets', '=', False)]}">
                     <field name="planned_hours" class="oe_inline" widget="float_time"/>
-                    <span attrs="{'invisible': ['|', ('allow_subtasks', '=', False), ('subtask_count', '=', 0)]}">
-                        (incl. <field name="subtask_planned_hours" nolabel="1" groups="project.group_subtask_project" widget="timesheet_uom_no_toggle" class="oe_inline"/> on
+                    <span attrs="{'invisible': [('subtask_count', '=', 0)]}">
+                        (incl. <field name="subtask_planned_hours" nolabel="1" widget="timesheet_uom_no_toggle" class="oe_inline"/> on
                         <span class="fw-bold text-dark"> Sub-tasks</span>)
                     </span>
                     <span>(<field name="progress" class="oe_inline" nolabel="1" widget="integer"/> %)</span>
@@ -78,20 +78,20 @@
                                 <label class="fw-bold" for="effective_hours" string="Days Spent" attrs="{'invisible': [('encode_uom_in_days', '=', False)]}"/>
                             </span>
                             <field name="effective_hours" widget="timesheet_uom" nolabel="1"/>
-                            <button name="action_view_subtask_timesheet" type="object" class="ps-0 border-0 oe_inline oe_link mb-2 o_td_label float-start" attrs="{'invisible' : ['|', ('allow_subtasks', '=', False), ('subtask_effective_hours', '=', 0.0)]}">
+                            <button name="action_view_subtask_timesheet" type="object" class="ps-0 border-0 oe_inline oe_link mb-2 o_td_label float-start" attrs="{'invisible' : [('subtask_effective_hours', '=', 0.0)]}">
                                 <span class="text-nowrap" attrs="{'invisible' : [('encode_uom_in_days', '=', True)]}">Hours Spent on Sub-tasks:</span>
                                 <span class="text-nowrap" attrs="{'invisible' : [('encode_uom_in_days', '=', False)]}">Days Spent on Sub-tasks:</span>
                             </button>
                             <field name="subtask_effective_hours" class="mt-2" widget="timesheet_uom"
-                                  attrs="{'invisible' : ['|', ('allow_subtasks', '=', False), ('subtask_effective_hours', '=', 0.0)]}" nolabel="1"/>
-                            <span id="total_hours_spent_label" attrs="{'invisible': ['|', ('allow_subtasks', '=', False), ('subtask_effective_hours', '=', 0.0)]}" class="o_td_label float-start">
+                                  attrs="{'invisible' : [('subtask_effective_hours', '=', 0.0)]}" nolabel="1"/>
+                            <span id="total_hours_spent_label" attrs="{'invisible': [('subtask_effective_hours', '=', 0.0)]}" class="o_td_label float-start">
                                 <label class="fw-bold" for="total_hours_spent" string="Total Hours"
                                       attrs="{'invisible': [('encode_uom_in_days', '=', True)]}"/>
                                 <label class="fw-bold" for="total_hours_spent" string="Total Days"
                                       attrs="{'invisible': [('encode_uom_in_days', '=', False)]}"/>
                             </span>
                             <field name="total_hours_spent" widget="timesheet_uom" class="oe_subtotal_footer_separator" nolabel="1"
-                                  attrs="{'invisible' : ['|', ('allow_subtasks', '=', False), ('subtask_effective_hours', '=', 0.0)]}" />
+                                  attrs="{'invisible' : [('subtask_effective_hours', '=', 0.0)]}" />
                             <span class="o_td_label float-start">
                                 <label class="fw-bold" for="remaining_hours" string="Remaining Hours"
                                        attrs="{'invisible': ['|', '|', ('planned_hours', '=', 0.0), ('encode_uom_in_days', '=', True), ('remaining_hours', '&lt;', 0)]}"/>
diff --git a/addons/hr_timesheet/views/project_task_views.xml b/addons/hr_timesheet/views/project_task_views.xml
index 2a58154e6f4..0af2d0e0bb6 100644
--- a/addons/hr_timesheet/views/project_task_views.xml
+++ b/addons/hr_timesheet/views/project_task_views.xml
@@ -20,8 +20,8 @@
                     <label for="planned_hours" attrs="{'invisible': [('allow_timesheets', '=', False)]}"/>
                     <div class="text-nowrap" attrs="{'invisible': [('allow_timesheets', '=', False)]}">
                         <field name="planned_hours" class="oe_inline" widget="float_time"/>
-                        <span attrs="{'invisible': ['|', ('allow_subtasks', '=', False), ('subtask_count', '=', 0)]}">
-                            (incl. <field name="subtask_planned_hours" nolabel="1" groups="project.group_subtask_project" widget="timesheet_uom_no_toggle" class="oe_inline"/> on
+                        <span attrs="{'invisible': [('subtask_count', '=', 0)]}">
+                            (incl. <field name="subtask_planned_hours" nolabel="1" widget="timesheet_uom_no_toggle" class="oe_inline"/> on
                             <span class="fw-bold text-dark"> Sub-tasks</span>)
                         </span>
                         <span attrs="{'invisible': [('project_id', '=', False)]}">(<field name="progress" class="oe_inline" nolabel="1" widget="integer"/> %)</span>
@@ -29,7 +29,6 @@
                 </xpath>
                 <xpath expr="//notebook/page[@name='description_page']" position="after">
                     <field name="allow_timesheets" invisible="1"/>
-                    <field name="allow_subtasks" invisible="1"/>
                     <t groups="hr_timesheet.group_hr_timesheet_user">
                         <field name="analytic_account_active" invisible="1"/>
                     </t>
@@ -111,20 +110,20 @@
                                 <label class="fw-bold" for="effective_hours" string="Days Spent" attrs="{'invisible': [('encode_uom_in_days', '=', False)]}"/>
                             </span>
                             <field name="effective_hours" widget="timesheet_uom" nolabel="1"/>
-                            <button name="action_view_subtask_timesheet" type="object" class="ps-0 border-0 oe_inline oe_link mb-2 o_td_label float-start" attrs="{'invisible' : ['|', ('allow_subtasks', '=', False), ('subtask_effective_hours', '=', 0.0)]}">
+                            <button name="action_view_subtask_timesheet" type="object" class="ps-0 border-0 oe_inline oe_link mb-2 o_td_label float-start" attrs="{'invisible' : [('subtask_effective_hours', '=', 0.0)]}">
                                 <span class="text-nowrap" attrs="{'invisible' : [('encode_uom_in_days', '=', True)]}">Hours Spent on Sub-tasks:</span>
                                 <span class="text-nowrap" attrs="{'invisible' : [('encode_uom_in_days', '=', False)]}">Days Spent on Sub-tasks:</span>
                             </button>
                             <field name="subtask_effective_hours" class="mt-2" widget="timesheet_uom"
-                                   attrs="{'invisible' : ['|', ('allow_subtasks', '=', False), ('subtask_effective_hours', '=', 0.0)]}" nolabel="1"/>
-                            <span attrs="{'invisible': ['|', ('allow_subtasks', '=', False), ('subtask_effective_hours', '=', 0.0)]}" class="o_td_label float-start">
+                                   attrs="{'invisible' : [('subtask_effective_hours', '=', 0.0)]}" nolabel="1"/>
+                            <span attrs="{'invisible': [('subtask_effective_hours', '=', 0.0)]}" class="o_td_label float-start">
                                 <label class="fw-bold" for="total_hours_spent" string="Total Hours"
-                                       attrs="{'invisible': ['|', '|', ('allow_subtasks', '=', False), ('subtask_effective_hours', '=', 0.0), ('encode_uom_in_days', '=', True)]}"/>
+                                       attrs="{'invisible': ['|', ('subtask_effective_hours', '=', 0.0), ('encode_uom_in_days', '=', True)]}"/>
                                 <label class="fw-bold" for="total_hours_spent" string="Total Days"
-                                       attrs="{'invisible': ['|', '|', ('allow_subtasks', '=', False), ('subtask_effective_hours', '=', 0.0), ('encode_uom_in_days', '=', False)]}"/>
+                                       attrs="{'invisible': ['|', ('subtask_effective_hours', '=', 0.0), ('encode_uom_in_days', '=', False)]}"/>
                             </span>
                             <field name="total_hours_spent" widget="timesheet_uom" class="oe_subtotal_footer_separator" nolabel="1"
-                                   attrs="{'invisible' : ['|', ('allow_subtasks', '=', False), ('subtask_effective_hours', '=', 0.0)]}" />
+                                   attrs="{'invisible' : [('subtask_effective_hours', '=', 0.0)]}" />
                             <span class="o_td_label float-start">
                                 <label class="fw-bold" for="remaining_hours" string="Remaining Hours"
                                        attrs="{'invisible': ['|', '|', ('planned_hours', '=', 0.0), ('encode_uom_in_days', '=', True), ('remaining_hours', '&lt;', 0)]}"/>
@@ -142,12 +141,11 @@
                 </page>
                 </xpath>
                 <xpath expr="//field[@name='depend_on_ids']/tree//field[@name='company_id']" position="after">
-                    <field name="allow_subtasks" invisible="1" groups="hr_timesheet.group_hr_timesheet_user"/>
                     <field name="progress" invisible="1" groups="hr_timesheet.group_hr_timesheet_user"/>
                     <field name="planned_hours" widget="timesheet_uom_no_toggle" sum="Total Allocated Time" optional="hide" groups="hr_timesheet.group_hr_timesheet_user"/>
                     <field name="effective_hours" widget="timesheet_uom" sum="Effective Hours" optional="hide" groups="hr_timesheet.group_hr_timesheet_user"/>
-                    <field name="subtask_effective_hours" widget="timesheet_uom" attrs="{'invisible' : [('allow_subtasks', '=', False)]}" optional="hide" groups="hr_timesheet.group_hr_timesheet_user"/>
-                    <field name="total_hours_spent" widget="timesheet_uom" attrs="{'invisible' : [('allow_subtasks', '=', False)]}" optional="hide" groups="hr_timesheet.group_hr_timesheet_user"/>
+                    <field name="subtask_effective_hours" widget="timesheet_uom" optional="hide" groups="hr_timesheet.group_hr_timesheet_user"/>
+                    <field name="total_hours_spent" widget="timesheet_uom" optional="hide" groups="hr_timesheet.group_hr_timesheet_user"/>
                     <field name="remaining_hours" widget="timesheet_uom" sum="Remaining Hours" optional="hide" decoration-danger="progress &gt;= 100" decoration-warning="progress &gt;= 80 and progress &lt; 100" groups="hr_timesheet.group_hr_timesheet_user"/>
                     <field name="progress" widget="progressbar" optional="hide" options="{'overflow_class': 'bg-danger'}" groups="hr_timesheet.group_hr_timesheet_user"/>
                 </xpath>
@@ -160,13 +158,12 @@
             <field name="inherit_id" ref="project.project_task_view_tree_main_base" />
             <field name="arch" type="xml">
                 <field name="date_deadline" position="before">
-                    <field name="allow_subtasks" invisible="1"/>
                     <field name="progress" invisible="1"/>
                     <field name="effective_hours" invisible="1"/>
                     <field name="planned_hours" widget="timesheet_uom_no_toggle" sum="Total Allocated Time" attrs="{'invisible' : [('planned_hours', '=', 0)]}" optional="hide"/>
                     <field name="effective_hours" widget="timesheet_uom" sum="Effective Hours" optional="show" attrs="{'invisible' : [('effective_hours', '=', 0)]}"/>
-                    <field name="subtask_effective_hours" widget="timesheet_uom" attrs="{'invisible' : [('allow_subtasks', '=', False)]}" optional="hide"/>
-                    <field name="total_hours_spent" widget="timesheet_uom" attrs="{'invisible' : [('allow_subtasks', '=', False)]}" optional="hide"/>
+                    <field name="subtask_effective_hours" widget="timesheet_uom" optional="hide"/>
+                    <field name="total_hours_spent" widget="timesheet_uom" optional="hide"/>
                     <field name="remaining_hours" widget="timesheet_uom" sum="Remaining Hours" optional="hide" decoration-danger="progress &gt;= 100" decoration-warning="progress &gt;= 80 and progress &lt; 100" attrs="{'invisible' : [('planned_hours', '=', 0)]}"/>
                     <field name="progress" widget="progressbar" optional="show" groups="hr_timesheet.group_hr_timesheet_user" attrs="{'invisible' : [('planned_hours', '=', 0)]}" options="{'overflow_class': 'bg-danger'}" />
                 </field>
diff --git a/addons/project/models/project_project.py b/addons/project/models/project_project.py
index 646aa061e50..8108b19b93d 100644
--- a/addons/project/models/project_project.py
+++ b/addons/project/models/project_project.py
@@ -160,7 +160,6 @@ class Project(models.Model):
     date_start = fields.Date(string='Start Date')
     date = fields.Date(string='Expiration Date', index=True, tracking=True,
         help="Date on which this project ends. The timeframe defined on the project is taken into account when viewing its planning.")
-    allow_subtasks = fields.Boolean('Sub-tasks', default=lambda self: self.env.user.has_group('project.group_subtask_project'))
     allow_recurring_tasks = fields.Boolean('Recurring Tasks', default=lambda self: self.env.user.has_group('project.group_project_recurring_tasks'))
     allow_task_dependencies = fields.Boolean('Task Dependencies', default=lambda self: self.env.user.has_group('project.group_project_task_dependencies'))
     allow_milestones = fields.Boolean('Milestones', default=lambda self: self.env.user.has_group('project.group_project_milestone'))
diff --git a/addons/project/models/project_task.py b/addons/project/models/project_task.py
index e415efd49cc..84a912a00f4 100644
--- a/addons/project/models/project_task.py
+++ b/addons/project/models/project_task.py
@@ -20,10 +20,8 @@ PROJECT_TASK_READABLE_FIELDS = {
     'priority',
     'project_id',
     'color',
-    'allow_subtasks',
     'subtask_count',
     'is_private',
-    'child_text',
     'email_from',
     'create_date',
     'write_date',
@@ -41,6 +39,7 @@ PROJECT_TASK_READABLE_FIELDS = {
     'dependent_ids',
     'message_is_follower',
     'recurring_task',
+    'closed_subtask_count',
 }
 
 PROJECT_TASK_WRITABLE_FIELDS = {
@@ -124,9 +123,8 @@ class Task(models.Model):
     stage_id = fields.Many2one('project.task.type', string='Stage', compute='_compute_stage_id',
         store=True, readonly=False, ondelete='restrict', tracking=True, index=True,
         default=_get_default_stage_id, group_expand='_read_group_stage_ids',
-        domain="[('project_ids', '=', project_id)]", copy=False, task_dependency_tracking=True)
-    tag_ids = fields.Many2many('project.tags', string='Tags',
-        help="You can only see tags that are already present in your project. If you try creating a tag that is already existing in other projects, it won't generate any duplicates.")
+        domain="[('project_ids', '=', project_id)]", task_dependency_tracking=True)
+    tag_ids = fields.Many2many('project.tags', string='Tags')
 
     state = fields.Selection([
         ('01_in_progress', 'In Progress'),
@@ -194,9 +192,8 @@ class Task(models.Model):
     is_closed = fields.Boolean(compute='_compute_is_closed', string="Closed State", store=True, index=True)
     parent_id = fields.Many2one('project.task', string='Parent Task', index=True)
     child_ids = fields.One2many('project.task', 'parent_id', string="Sub-tasks", domain="[('recurring_task', '=', False)]")
-    child_text = fields.Char(compute="_compute_child_text")
-    allow_subtasks = fields.Boolean(string="Allow Sub-tasks", related="project_id.allow_subtasks", readonly=True)
     subtask_count = fields.Integer("Sub-task Count", compute='_compute_subtask_count')
+    closed_subtask_count = fields.Integer("Closed Sub-tasks Count", compute='_compute_subtask_count')
     project_privacy_visibility = fields.Selection(related='project_id.privacy_visibility', string="Project Visibility")
     # Computed field about working time elapsed between record creation and assignation/closing.
     working_hours_open = fields.Float(compute='_compute_elapsed', string='Working Hours to Assign', digits=(16, 2), store=True, group_operator="avg")
@@ -222,8 +219,6 @@ class Task(models.Model):
         compute='_compute_has_late_and_unreached_milestone',
         search='_search_has_late_and_unreached_milestone',
     )
-    #used to display the stage of the task in the tree view (if the project is private will return the personnal_stage_id, else will return the stage_id)
-    stage_display = fields.Char(compute='_compute_stage_display', string='Stage Display')
     # Task Dependencies fields
     allow_task_dependencies = fields.Boolean(related='project_id.allow_task_dependencies')
     # Tracking of this field is done in the write function
@@ -525,20 +520,20 @@ class Task(models.Model):
         for task in self:
             task.subtask_planned_hours = sum(child_task.planned_hours + child_task.subtask_planned_hours for child_task in task.child_ids)
 
-    @api.depends('child_ids')
-    def _compute_child_text(self):
-        for task in self:
-            if not task.subtask_count:
-                task.child_text = False
-            elif task.subtask_count == 1:
-                task.child_text = _("(+ 1 task)")
-            else:
-                task.child_text = _("(+ %(child_count)s tasks)", child_count=task.subtask_count)
-
     @api.depends('child_ids')
     def _compute_subtask_count(self):
+        total_and_closed_subtask_count_per_parent_id = {
+            group['parent_id'][0]: (
+                group['parent_id_count'],
+                sum(s in CLOSED_STATES for s in group['state']),
+            ) for group in self.env['project.task']._read_group(
+                [('parent_id', 'in', self.ids)],
+                ['state:array_agg', 'parent_id'],
+                ['parent_id'],
+            )
+        }
         for task in self:
-            task.subtask_count = len(task._get_all_subtasks())
+            task.subtask_count, task.closed_subtask_count = total_and_closed_subtask_count_per_parent_id.get(task.id, (0, 0))
 
     @api.onchange('company_id')
     def _onchange_task_company(self):
@@ -561,11 +556,6 @@ class Task(models.Model):
             else:
                 task.stage_id = False
 
-    @api.depends('project_id', 'stage_id', 'personal_stage_id')
-    def _compute_stage_display(self):
-        for task in self:
-            task.stage_display = task.stage_id.name if task.project_id else task.personal_stage_id.stage_id.name
-
     @api.depends('user_ids')
     def _compute_portal_user_names(self):
         """ This compute method allows to see all the names of assigned users to each task contained in `self`.
@@ -676,8 +666,7 @@ class Task(models.Model):
             default['name'] = _("%s (copy)", self.name)
         if self.recurrence_id:
             default['recurrence_id'] = self.recurrence_id.copy().id
-        if self.allow_subtasks:
-            default['child_ids'] = [child.copy({'name': child.name} if has_default_name else None).id for child in self.child_ids]
+        default['child_ids'] = [child.copy({'name': child.name}).id for child in self.child_ids]
         self_with_mail_context = self.with_context(mail_auto_subscribe_no_notify=True, mail_create_nosubscribe=True)
         task_copy = super(Task, self_with_mail_context).copy(default)
         if self.allow_task_dependencies:
diff --git a/addons/project/models/project_task_recurrence.py b/addons/project/models/project_task_recurrence.py
index c20b15c994b..c78ac396003 100644
--- a/addons/project/models/project_task_recurrence.py
+++ b/addons/project/models/project_task_recurrence.py
@@ -102,8 +102,7 @@ class ProjectTaskRecurrence(models.Model):
         })
 
         create_values['stage_id'] = occurrence_from.project_id.type_ids[0].id if occurrence_from.project_id.type_ids else occurrence_from.stage_id.id
-        if occurrence_from.allow_subtasks:
-            create_values['child_ids'] = [
-                Command.create(self._create_next_occurrence_values(child)) for child in occurrence_from.with_context(active_test=False).child_ids
-            ]
+        create_values['child_ids'] = [
+            Command.create(self._create_next_occurrence_values(child)) for child in occurrence_from.with_context(active_test=False).child_ids
+        ]
         return create_values
diff --git a/addons/project/models/res_config_settings.py b/addons/project/models/res_config_settings.py
index aabb7aae890..7255f196fe9 100644
--- a/addons/project/models/res_config_settings.py
+++ b/addons/project/models/res_config_settings.py
@@ -9,7 +9,6 @@ class ResConfigSettings(models.TransientModel):
 
     module_project_forecast = fields.Boolean(string="Planning")
     module_hr_timesheet = fields.Boolean(string="Task Logs")
-    group_subtask_project = fields.Boolean("Sub-tasks", implied_group="project.group_subtask_project")
     group_project_rating = fields.Boolean("Customer Ratings", implied_group='project.group_project_rating')
     group_project_stages = fields.Boolean("Project Stages", implied_group="project.group_project_stages")
     group_project_recurring_tasks = fields.Boolean("Recurring Tasks", implied_group="project.group_project_recurring_tasks")
@@ -37,7 +36,6 @@ class ResConfigSettings(models.TransientModel):
             # key: (config_flag, is_global), value: project_flag
             ("group_project_rating", True): "rating_active",
             ("group_project_recurring_tasks", True): "allow_recurring_tasks",
-            ("group_subtask_project", False): "allow_subtasks",
             ("group_project_task_dependencies", False): "allow_task_dependencies",
             ("group_project_milestone", False): "allow_milestones",
         }
diff --git a/addons/project/security/project_security.xml b/addons/project/security/project_security.xml
index 11cb810f365..af8cbacb95a 100644
--- a/addons/project/security/project_security.xml
+++ b/addons/project/security/project_security.xml
@@ -19,11 +19,6 @@
         <field name="users" eval="[(4, ref('base.user_root')), (4, ref('base.user_admin'))]"/>
     </record>
 
-    <record id="group_subtask_project" model="res.groups">
-        <field name="name">Use Subtasks</field>
-        <field name="category_id" ref="base.module_category_hidden"/>
-    </record>
-
     <record id="group_project_rating" model="res.groups">
         <field name="name">Use Rating on Project</field>
         <field name="category_id" ref="base.module_category_hidden"/>
diff --git a/addons/project/static/src/components/project_task_name_with_subtask_count_char_field/project_task_name_with_subtask_count_char_field.js b/addons/project/static/src/components/project_task_name_with_subtask_count_char_field/project_task_name_with_subtask_count_char_field.js
index 0cc014f92c9..e3e9357b219 100644
--- a/addons/project/static/src/components/project_task_name_with_subtask_count_char_field/project_task_name_with_subtask_count_char_field.js
+++ b/addons/project/static/src/components/project_task_name_with_subtask_count_char_field/project_task_name_with_subtask_count_char_field.js
@@ -2,11 +2,12 @@
 
 import { registry } from '@web/core/registry';
 import { CharField, charField } from '@web/views/fields/char/char_field';
-import { formatChar } from '@web/views/fields/formatters';
 
 class ProjectTaskNameWithSubtaskCountCharField extends CharField {
     get formattedSubtaskCount() {
-        return formatChar(this.props.record.data.allow_subtasks && this.props.record.data.child_text || '');
+            return this.props.record.data.subtask_count
+                ? `(${this.props.record.data.closed_subtask_count}/${this.props.record.data.subtask_count} subtasks)`
+                : "";
     }
 }
 
diff --git a/addons/project/static/src/components/project_task_name_with_subtask_count_char_field/project_task_name_with_subtask_count_char_field.xml b/addons/project/static/src/components/project_task_name_with_subtask_count_char_field/project_task_name_with_subtask_count_char_field.xml
index 1d75a408040..1bb18e7dc37 100644
--- a/addons/project/static/src/components/project_task_name_with_subtask_count_char_field/project_task_name_with_subtask_count_char_field.xml
+++ b/addons/project/static/src/components/project_task_name_with_subtask_count_char_field/project_task_name_with_subtask_count_char_field.xml
@@ -2,12 +2,6 @@
 <templates xml:space="preserve">
 
     <t t-name="project.ProjectTaskNameWithSubtaskCountCharField" t-inherit="web.CharField" t-inherit-mode="primary" owl="1">
-        <xpath expr="//span[@t-esc='formattedValue']" position="before">
-            <s t-if="['1_done', '1_canceled'].includes(this.props.record.data.state) and ['kanban', 'list'].includes(this.props.record.activeFields[this.props.name].viewType)" t-esc="formattedValue"/>
-        </xpath>
-        <xpath expr="//span[@t-esc='formattedValue']" position="attributes">
-            <attribute name="t-else">""</attribute>
-        </xpath>
         <xpath expr="//span[@t-esc='formattedValue']" position="after">
             <span
                 class="text-muted ms-2"
diff --git a/addons/project/static/src/components/project_task_state_selection/project_task_state_selection.js b/addons/project/static/src/components/project_task_state_selection/project_task_state_selection.js
index 9c14ee9d03b..51584f5ba61 100644
--- a/addons/project/static/src/components/project_task_state_selection/project_task_state_selection.js
+++ b/addons/project/static/src/components/project_task_state_selection/project_task_state_selection.js
@@ -112,20 +112,24 @@ export class ProjectTaskStateSelection extends StateSelectionField {
         return this.props.isToggleMode || !this.props.record.data.project_id;
     }
 
+    isView(viewNames) {
+        return viewNames.includes(this.props.viewType);
+    }
+
     async toggleState() {
         const toggleVal = this.currentValue == "1_done" ? "01_in_progress" : "1_done";
         await this.updateRecord(toggleVal);
     }
 
     getDropdownPosition() {
-        if (['kanban', 'list'].includes(this.props.viewType) || this.env.isSmall) {
+        if (this.isView(['kanban', 'list']) || this.env.isSmall) {
             return '';
         }
         return 'bottom-end';
     }
 
     getTogglerClass(currentValue) {
-        if (['kanban', 'list'].includes(this.props.viewType) || this.env.isSmall) {
+        if (this.isView(['kanban', 'list']) || this.env.isSmall) {
             return 'btn btn-link d-flex p-0';
         }
         return 'o_state_button btn rounded-pill ' + this.colorButton[currentValue];
diff --git a/addons/project/static/src/components/project_task_state_selection/project_task_state_selection.scss b/addons/project/static/src/components/project_task_state_selection/project_task_state_selection.scss
index 00cceee43c1..a95b96e80db 100644
--- a/addons/project/static/src/components/project_task_state_selection/project_task_state_selection.scss
+++ b/addons/project/static/src/components/project_task_state_selection/project_task_state_selection.scss
@@ -1,25 +1,56 @@
 .o_field_project_task_state_selection{
     .o_status {
-        width: 14.65px;
-        height: 14.65px;
+        width: 19.5px;
+        height: 19.5px;
         text-align: center;
+        margin-top: -0.5px;
+    }
+
+    .fa-lg {
+        font-size: 1.75em;
+        margin-top: -2.5px;
+        max-width: 20px;
+        max-height: 20px;
     }
 
     .o_color_bubble_22 {
         background-color: #ffac00;
     }
 
-    .dropdown-item .fa {
-        transform: translateX(-50%);
+    .fa-hourglass-o {
+        font-size: 1.4em !important;
+        margin-top: 0.5px !important;
     }
 
-    .fa-hourglass-o{
-        font-size: 1.15em;
-        padding-left: 1px;
+    .o_task_state_list_view {
+        .fa-lg {
+            font-size: 1.315em;
+            vertical-align: -6%;
+        }
+        .o_status {
+            width: 14.65px;
+            height: 14.65px;
+            text-align: center;
+        }
+        .fa-hourglass-o {
+            font-size: 1.15em !important;
+            padding-left: 1px !important;
+        }
     }
-}
 
-// This negative margin is only useful in list_view
-.o_data_cell .o_field_project_task_state_selection .dropdown-toggle .fa{
-    margin-top: -1.22px;
+    .dropdown-menu {
+        .fa {
+            margin-top: -1.5px;
+            font-size: 1.315em;
+            vertical-align: -6%;
+            transform: translateX(-50%);
+        }
+
+        .o_status {
+            margin-top: 1px;
+            width: 14.65px;
+            height: 14.65px;
+            text-align: center;
+        }
+    }   
 }
diff --git a/addons/project/static/src/components/project_task_state_selection/project_task_state_selection.xml b/addons/project/static/src/components/project_task_state_selection/project_task_state_selection.xml
index 91b417c6ccc..01fa04f737a 100644
--- a/addons/project/static/src/components/project_task_state_selection/project_task_state_selection.xml
+++ b/addons/project/static/src/components/project_task_state_selection/project_task_state_selection.xml
@@ -6,8 +6,8 @@
         </xpath>
         <!-- Waiting state button -->
         <xpath expr="//t[@t-if='props.readonly']" position="after">
-            <t t-elif="currentValue == '04_waiting_normal' and ['kanban', 'list'].includes(this.props.viewType)">
-                <button class="d-flex align-items-center btn fw-normal p-0 justify-content-center " title="This task is blocked by another unfinished task">
+            <t t-elif="currentValue == '04_waiting_normal' and isView(['kanban', 'list'])">
+                <button class="d-flex align-items-center btn fw-normal p-0 justify-content-center " title="This task is blocked by another unfinished task" t-att-class="{'o_task_state_list_view': isView(['list'])}">
                     <i class="fa fa-lg fa-hourglass-o"></i>
                 </button>
             </t>
@@ -15,11 +15,11 @@
         <!-- The toggle mark as done button -->
         <xpath expr="//t[@t-if='props.readonly']" position="after">
             <t t-elif="isToggleMode and currentValue == '01_in_progress'">
-                <button t-if="['kanban', 'list'].includes(this.props.viewType) or this.env.isSmall" class="d-flex align-items-center btn fw-normal p-0" t-on-click.stop="toggleState">
-                    <i t-attf-class="{{ stateIcon(currentValue) }} {{ statusColor(currentValue) }}"></i>
+                <button t-if="isView(['kanban', 'list']) or this.env.isSmall" class="d-flex align-items-center btn fw-normal p-0" t-on-click.stop="toggleState" t-att-class="{'o_task_state_list_view': isView(['list'])}">
+                    <i t-attf-class="{{ stateIcon(currentValue) }} {{ statusColor(currentValue) }} {{ ['1_done', '1_canceled'].includes(currentValue) and isView(['kanban']) ? 'opacity-50' : '' }}"></i>
                 </button>
                 <button t-else="" class="o_state_button btn oe_highlight rounded-pill" style="white-space: nowrap;"
-                    t-attf-class="{ #{currentValue == '1_done' ? 'btn-success' : 'btn-light border-2 border-dark'} }"
+                    t-att-class="currentValue == '1_done' ? 'btn-success' : 'btn-light border-2 border-dark'"
                     t-on-click="toggleState" t-on-mouseenter="onMouseEnterStateButton"
                     t-on-mouseleave="onMouseLeaveStateButton">
                     <div class="d-flex align-items-center">
@@ -41,9 +41,9 @@
 
         <!-- Normal dropdown mode toggle button (displayed on the card/record by default) -->
         <xpath expr="//t[@t-set-slot='toggler']/div" position="replace">
-            <div t-if="['kanban', 'list'].includes(this.props.viewType) or this.env.isSmall" class="d-flex align-items-center">
+            <div t-if="isView(['kanban', 'list']) or this.env.isSmall" class="d-flex align-items-center" t-att-class="{'o_task_state_list_view': isView(['list'])}">
                 <i t-if="currentValue == '04_waiting_normal'" t-attf-class="{{ stateIcon(currentValue) }} {{ statusColor(currentValue) }}" style="color: #4A4F59;"/>
-                <i t-else="" t-attf-class="{{ stateIcon(currentValue) }} {{ statusColor(currentValue) }}"/>
+                <i t-else="" t-attf-class="{{ stateIcon(currentValue) }} {{ statusColor(currentValue) }} {{ ['1_done', '1_canceled'].includes(currentValue) and isView(['kanban']) ? 'opacity-50' : '' }}"/>
             </div>
             <div t-else="" class="d-flex align-items-center">
                 <t t-if="currentValue == '04_waiting_normal'">
diff --git a/addons/project/static/src/components/subtask_kanban_list/subtask_kanban_list.js b/addons/project/static/src/components/subtask_kanban_list/subtask_kanban_list.js
index 7c41a3f378b..5910d0222ec 100644
--- a/addons/project/static/src/components/subtask_kanban_list/subtask_kanban_list.js
+++ b/addons/project/static/src/components/subtask_kanban_list/subtask_kanban_list.js
@@ -3,7 +3,7 @@
 import { useService } from "@web/core/utils/hooks";
 
 import { registry } from "@web/core/registry";
-import { Component } from "@odoo/owl";
+import { Component, onWillStart } from "@odoo/owl";
 import { Record } from "@web/views/record";
 import { KanbanMany2ManyTagsAvatarUserField } from "@mail/web/fields/many2many_avatar_user_field/many2many_avatar_user_field";
 import { Field } from "@web/views/fields/field";
@@ -12,6 +12,17 @@ import { standardWidgetProps } from "@web/views/widgets/standard_widget_props";
 export class SubtaskKanbanList extends Component {
     setup() {
         this.actionService = useService("action");
+        this.orm = useService("orm");
+        this.subTaskIds = [];
+
+        onWillStart(this.onWillStart);
+    }
+
+    async onWillStart() {
+        this.subTaskIds = await this.orm.search(this.props.record.resModel, [
+            ["parent_id", "=", this.props.record.resId],
+            ["state", "not in", ["1_done", "1_canceled"]],
+        ]);
     }
 
     async goToSubtask(subtask_id) {
@@ -62,6 +73,10 @@ export class SubtaskKanbanList extends Component {
             },
         };
     }
+
+    get values() {
+        return { child_ids: this.subTaskIds };
+    }
 }
 
 SubtaskKanbanList.components = {
diff --git a/addons/project/static/src/components/subtask_kanban_list/subtask_kanban_list.scss b/addons/project/static/src/components/subtask_kanban_list/subtask_kanban_list.scss
index 9045e926181..2017928422f 100644
--- a/addons/project/static/src/components/subtask_kanban_list/subtask_kanban_list.scss
+++ b/addons/project/static/src/components/subtask_kanban_list/subtask_kanban_list.scss
@@ -3,8 +3,7 @@
 
     .subtask_list_row {
         display: grid;
-        grid-template-columns: 20px auto auto;
-        column-gap: 4px;
+        grid-template-columns: auto auto 22px;
         padding: 4px 0px;
 
         .subtask_name_col {
diff --git a/addons/project/static/src/components/subtask_kanban_list/subtask_kanban_list.xml b/addons/project/static/src/components/subtask_kanban_list/subtask_kanban_list.xml
index 613db9c0b2f..5c2438513b3 100644
--- a/addons/project/static/src/components/subtask_kanban_list/subtask_kanban_list.xml
+++ b/addons/project/static/src/components/subtask_kanban_list/subtask_kanban_list.xml
@@ -3,27 +3,27 @@
 <templates>
 
     <t t-name="project.SubtaskKanbanList" owl="1">
-        <Record resModel="'project.task'" resId="props.record.resId" fields="fieldsInfo" activeFields="fieldsInfo" t-slot-scope="data">
+        <Record resModel="'project.task'" resId="props.record.resId" fields="fieldsInfo" activeFields="fieldsInfo" values="values" t-slot-scope="data">
             <div class="subtask_list">
                 <t t-foreach="data.record.data.child_ids.records" t-as="subTask" t-key="subTask.resId">
                     <div class="subtask_list_row">
-                        <Field name="'state'"
-                               class="`subtask_state_widget_col d-flex justify-content-center align-items-center`"
-                               record="subTask"
-                               fieldInfo="subTask.fields.state"
-                               type="'project_task_state_selection'"/>
-                        <a class="subtask_name_col"
+                        <a t-attf-class="subtask_name_col {{['1_done', '1_canceled'].includes(subTask.data.state) ? 'text-muted opacity-50' : ''}}"
                            t-att-title="subTask.data.display_name"
                            style="color: inherit;"
                            t-esc="subTask.data.display_name"
                            t-on-click.prevent="() => this.goToSubtask(subTask.resId)"/>
                         <Field
-                               class="`subtask_user_widget_col justify-content-end align-items-center`"
+                               class="`subtask_user_widget_col justify-content-end align-items-center ${['1_done', '1_canceled'].includes(subTask.data.state) ? 'opacity-50' : ''}`"
                                name="'user_ids'"
                                record="subTask"
                                fieldInfo="subTask.fields.user_ids"
                                readonly="true"
                                type="'many2many_avatar_user'"/>
+                        <Field name="'state'"
+                               class="`subtask_state_widget_col d-flex justify-content-center align-items-center`"
+                               record="subTask"
+                               fieldInfo="subTask.fields.state"
+                               type="'project_task_state_selection'"/>
                     </div>
                 </t>
             </div>
diff --git a/addons/project/static/src/scss/project_widgets.scss b/addons/project/static/src/scss/project_widgets.scss
index c08884bf223..815534ae13b 100644
--- a/addons/project/static/src/scss/project_widgets.scss
+++ b/addons/project/static/src/scss/project_widgets.scss
@@ -62,3 +62,11 @@
         width: 5%;
     }
 }
+
+.o_field_project_state_selection {
+    .dropdown-toggle .o_status {
+        width: 19px;
+        height: 19px;
+        text-align: center;
+    }
+}
diff --git a/addons/project/static/src/views/project_task_kanban/project_task_kanban_compiler.js b/addons/project/static/src/views/project_task_kanban/project_task_kanban_compiler.js
index 3421910afe0..3f92fdeb904 100644
--- a/addons/project/static/src/views/project_task_kanban/project_task_kanban_compiler.js
+++ b/addons/project/static/src/views/project_task_kanban/project_task_kanban_compiler.js
@@ -23,8 +23,6 @@ export class ProjectTaskKanbanCompiler extends KanbanCompiler {
     compileSubtaskListButton(el) {
         this.subtaskListComponentCompiled.button = true;
         el.setAttribute("t-on-click", `() => __comp__.state.folded = !__comp__.state.folded`);
-        el.removeAttribute("class");
-        el.setAttribute("t-attf-class", "subtask_list_button btn fa {{ state.folded ? 'fa-solid fa-angle-right' : 'fa-solid fa-angle-down' }}");
         const compiled = createElement(el.nodeName);
         for (const { name, value } of el.attributes) {
             compiled.setAttribute(name, value);
diff --git a/addons/project/static/src/views/project_task_kanban/project_task_kanban_view.scss b/addons/project/static/src/views/project_task_kanban/project_task_kanban_view.scss
index b2928cd514a..54f26f2a05d 100644
--- a/addons/project/static/src/views/project_task_kanban/project_task_kanban_view.scss
+++ b/addons/project/static/src/views/project_task_kanban/project_task_kanban_view.scss
@@ -2,4 +2,11 @@
     div.o_field_many2many_avatar_user[name="user_ids"] {
         margin-left: 6px;
     }
+
+    .rating_face {
+        font-weight: bold;
+        padding-top: 2px;
+        padding-right: 3px;
+        font-size: 16px;
+    }
 }
diff --git a/addons/project/static/src/views/project_task_list/project_task_list_renderer.js b/addons/project/static/src/views/project_task_list/project_task_list_renderer.js
new file mode 100644
index 00000000000..e1d01a68546
--- /dev/null
+++ b/addons/project/static/src/views/project_task_list/project_task_list_renderer.js
@@ -0,0 +1,18 @@
+/** @odoo-module */
+
+import { ListRenderer } from "@web/views/list/list_renderer";
+import { getRawValue } from "@web/views/kanban/kanban_record";
+
+export class ProjectTaskListRenderer extends ListRenderer {
+    getCellReadonly(column, record) {
+        let readonly = false;
+        const selection = this.props.list.selection;
+        if (column.name === "stage_id" && selection.length) {
+            const projectId = getRawValue(selection[0], "project_id");
+            readonly = selection.some(
+                (task) => getRawValue(task, "project_id") !== projectId
+            );
+        }
+        return readonly || super.getCellReadonly(column, record);
+    }
+}
diff --git a/addons/project/static/src/views/project_task_list/project_task_list_view.js b/addons/project/static/src/views/project_task_list/project_task_list_view.js
index 13299b1eea8..12bea3de3eb 100644
--- a/addons/project/static/src/views/project_task_list/project_task_list_view.js
+++ b/addons/project/static/src/views/project_task_list/project_task_list_view.js
@@ -3,10 +3,12 @@
 import { registry } from "@web/core/registry";
 import { listView } from '@web/views/list/list_view';
 import { ProjectControlPanel } from "../../components/project_control_panel/project_control_panel";
+import { ProjectTaskListRenderer } from "./project_task_list_renderer";
 
 export const projectTaskListView = {
     ...listView,
     ControlPanel: ProjectControlPanel,
+    Renderer: ProjectTaskListRenderer,
 };
 
 registry.category("views").add("project_task_list", projectTaskListView);
diff --git a/addons/project/static/tests/project_subtask_kanban_list_tests.js b/addons/project/static/tests/project_subtask_kanban_list_tests.js
index 833791e1582..3713538d94a 100644
--- a/addons/project/static/tests/project_subtask_kanban_list_tests.js
+++ b/addons/project/static/tests/project_subtask_kanban_list_tests.js
@@ -18,28 +18,34 @@ QUnit.module('Subtask Kanban List tests', {
     beforeEach: async function () {
         const pyEnv = await startServer();
         const projectId = pyEnv['project.project'].create([
-            { name: "Project One", allow_subtasks: true },
+            { name: "Project One" },
         ]);
         const userId = pyEnv['res.users'].create([
             { name: "User One", login: 'one', password: 'one' },
         ]);
         pyEnv['project.task'].create([
-            { name: 'task one', project_id: projectId, subtask_count: 2, child_ids: [2, 3], state: '01_in_progress', user_ids: [userId] },
-            { name: 'task two', subtask_count: 0, child_ids: [], state: '03_approved' },
-            { name: 'task three', subtask_count: 0, child_ids: [], state: '02_changes_requested' },
-            { name: 'task four', project_id: projectId, subtask_count: 0, child_ids: [], state: '01_in_progress' },
+            { name: 'task one', project_id: projectId, closed_subtask_count: 2, subtask_count: 3, child_ids: [2, 3, 4], state: '01_in_progress', user_ids: [userId] },
+            { name: 'task two', parent_id: 1, closed_subtask_count: 0, subtask_count: 0, child_ids: [], state: '03_approved' },
+            { name: 'task three', parent_id: 1, closed_subtask_count: 0, subtask_count: 0, child_ids: [], state: '02_changes_requested' },
+            { name: 'task four', parent_id: 1, closed_subtask_count: 0, subtask_count: 0, child_ids: [], state: '1_done' },
+            { name: 'task five', closed_subtask_count: 0, subtask_count: 1, child_ids: [6], state: '03_approved' },
+            { name: 'task six', parent_id: 5, closed_subtask_count: 0, subtask_count: 0, child_ids: [], state: '1_canceled' },
         ]);
         this.views = {
             "project.task,false,kanban":
                 `<kanban js_class="project_task_kanban">
                     <field name="subtask_count"/>
+                    <field name="closed_subtask_count"/>
                     <templates>
                         <t t-name="kanban-box">
                             <div>
                                 <field name="name" widget="name_with_subtask_count"/>
                                 <field name="user_ids" invisible="1"/>
                                 <field name="state" invisible="1"/>
-                                <a t-if="record.subtask_count.raw_value" class="subtask_list_button" title="See Subtasks" style="width: 29px;"/>
+                                <a t-if="record.closed_subtask_count.raw_value">
+                                    <span title="See Subtasks" class="subtask_list_button fa fa-check-square-o me-1"/>
+                                    <t t-out="record.closed_subtask_count.value"/>/<t t-out="record.subtask_count.value"/>
+                                </a>
                             </div>
                             <div class="kanban_bottom_subtasks_section"/>
                         </t>
@@ -60,13 +66,13 @@ QUnit.module('Subtask Kanban List tests', {
             views: [[false, "kanban"]],
         });
 
-        assert.containsOnce(target, '.subtask_list_button', "Only kanban boxes of parent tasks should have the drawdown button, in this case this is 1");
+        assert.containsOnce(target, '.subtask_list_button', "Only kanban boxes of parent tasks having open subtasks should have the drawdown button, in this case this is 1");
         assert.containsNone(target, '.subtask_list', "If the drawdown button is not clicked, the subtasks list should be hidden");
 
         await click(target, '.subtask_list_button');
 
         assert.containsOnce(target, '.subtask_list', "Clicking on the button should make the subtask list render, in this case we are expectig 1 list");
-        assert.containsN(target, '.subtask_list_row', 2, "The list rendered should show all the subtasks of the task, in this case 2");
+        assert.containsN(target, '.subtask_list_row', 2, "The list rendered should show the open subtasks of the task, in this case 2");
         assert.containsN(target, '.subtask_state_widget_col', 2, "Each of the list's rows should have 1 state widget, thus we are looking for 2 in total");
         assert.containsN(target, '.subtask_user_widget_col', 2, "Each of the list's rows should have 1 user widgets, thus we are looking for 2 in total");
         assert.containsN(target, '.subtask_name_col', 2, "Each of the list's rows should display the subtask's name, thus we are looking for 2 in total");
diff --git a/addons/project/tests/test_multicompany.py b/addons/project/tests/test_multicompany.py
index 2a158b5b6b1..11e88721b18 100644
--- a/addons/project/tests/test_multicompany.py
+++ b/addons/project/tests/test_multicompany.py
@@ -260,12 +260,7 @@ class TestMultiCompanyProject(TestMultiCompanyCommon):
                 self.task_2.write({'project_id': False})
                 # For `parent_id` to  be visible in the view, you need
                 # 1. The debug mode
-                # 2. `allow_subtasks` to be true
-                # <field name="parent_id" attrs="{'invisible': [('allow_subtasks', '=', False)]}" groups="base.group_no_one"/>
-                # `allow_subtasks` is a related to `allow_subtasks` on the project
-                # as the point of the test is to test the behavior of the task `_compute_project_id` when there is no project,
-                # `allow_subtasks` is by default invisible, and you shouldn't therefore be able to change it.
-                # So, to make it visible, temporary modify the view to make it visible even when `allow_subtasks` is `False`.
+                # <field name="parent_id" groups="base.group_no_one"/>
                 view = self.env.ref('project.view_task_form2').sudo()
                 tree = etree.fromstring(view.arch)
                 for node in tree.xpath('//field[@name="parent_id"][@attrs]'):
@@ -281,17 +276,10 @@ class TestMultiCompanyProject(TestMultiCompanyCommon):
                 self.assertEqual(task.company_id, self.task_1.company_id, "The company of the subtask should be the one from its parent when no project is set.")
 
     def test_cross_subtask_project(self):
-        # set up default subtask project
-        self.project_company_a.write({'allow_subtasks': True})
 
         # For `parent_id` to  be visible in the view, you need
         # 1. The debug mode
-        # 2. `allow_subtasks` to be true
-        # <field name="parent_id" attrs="{'invisible': [('allow_subtasks', '=', False)]}" groups="base.group_no_one"/>
-        # `allow_subtasks` is a related to `allow_subtasks` on the project
-        # as the point of the test is to test the behavior of the task `_compute_project_id` when there is no project,
-        # `allow_subtasks` is by default invisible, and you shouldn't therefore be able to change it.
-        # So, to make it visible, temporary modify the view to make it visible even when `allow_subtasks` is `False`.
+        # <field name="parent_id" groups="base.group_no_one"/>
         view = self.env.ref('project.view_task_form2').sudo()
         tree = etree.fromstring(view.arch)
         for node in tree.xpath('//field[@name="parent_id"][@attrs]'):
diff --git a/addons/project/tests/test_project_config.py b/addons/project/tests/test_project_config.py
index e84c648aa22..2662509c367 100644
--- a/addons/project/tests/test_project_config.py
+++ b/addons/project/tests/test_project_config.py
@@ -17,7 +17,6 @@ class TestProjectConfig(TestProjectCommon):
         cls.Settings = cls.env["res.config.settings"]
         cls.features = (
             # Pairs of associated (config_flag, project_flag)
-            ("group_subtask_project", "allow_subtasks"),
             ("group_project_recurring_tasks", "allow_recurring_tasks"),
             ("group_project_rating", "rating_active"),
             )
diff --git a/addons/project/tests/test_project_sharing.py b/addons/project/tests/test_project_sharing.py
index 94d73d1bf84..177f8e83992 100644
--- a/addons/project/tests/test_project_sharing.py
+++ b/addons/project/tests/test_project_sharing.py
@@ -145,10 +145,6 @@ class TestProjectSharing(TestProjectSharingCommon):
             3.2) Create a sub-task
             3.3) Create a second sub-task
         """
-        # 0) Allow to create subtasks in the project tasks
-        # Required for `child_ids` to be visible in the view
-        # {'invisible': [('allow_subtasks', '=', False)]}
-        self.project_cows.allow_subtasks = True
         # 1) Give the 'read' access mode to a portal user in a project and try to create task with this user.
         with self.assertRaises(AccessError, msg="Should not accept the portal user create a task in the project when he has not the edit access right."):
             with self.get_project_sharing_form_view(self.task_cow.with_context({'tracking_disable': True, 'default_project_id': self.project_cows.id}), self.user_portal) as form:
diff --git a/addons/project/tests/test_project_subtasks.py b/addons/project/tests/test_project_subtasks.py
index 35d6bf29bef..5e4264f62af 100644
--- a/addons/project/tests/test_project_subtasks.py
+++ b/addons/project/tests/test_project_subtasks.py
@@ -8,15 +8,6 @@ from odoo.tests.common import Form
 @tagged('-at_install', 'post_install')
 class TestProjectSubtasks(TestProjectCommon):
 
-    @classmethod
-    def setUpClass(cls):
-        super().setUpClass()
-
-        # Enable the company setting
-        cls.env['res.config.settings'].create({
-            'group_subtask_project': True
-        }).execute()
-
     def test_task_display_project_with_default_form(self):
         """
             Create a task in the default task form should take the project set in the form or the default project in the context
@@ -92,7 +83,8 @@ class TestProjectSubtasks(TestProjectCommon):
             6) Remove parent task:
                 - The project id should remain unchanged
             7) Remove project id then parent id:
-                - should not be possible since allow_subtasks is false when no project is set on the subtask
+                - Project should be removed
+                - Parent should be removed
         """
         # 1)
         with Form(self.task_1.with_context({'tracking_disable': True})) as task_form:
@@ -149,12 +141,11 @@ class TestProjectSubtasks(TestProjectCommon):
                     child_task_form.project_id = self.project_goats
             with Form(self.task_1.child_ids.with_context({'tracking_disable': True})) as subtask_form:
                 subtask_form.project_id = self.env['project.project']
-                with self.assertRaises(AssertionError, msg="the parent_id field should not be visible since no project is set on the subtask and so allow_subtasks is false"):
-                    subtask_form.parent_id = self.env['project.task']
+                subtask_form.parent_id = self.env['project.task']
             orphan_subtask = subtask_form.save()
 
             self.assertFalse(orphan_subtask.project_id, "The project should be removed as expected.")
-            self.assertEqual(orphan_subtask.parent_id, self.task_1, "The parent should not be removed since the field was not there in the form view after project had been removed.")
+            self.assertFalse(orphan_subtask.project_id, "The Parent should be removed as expected.")
 
     def test_subtask_stage(self):
         """
@@ -208,25 +199,31 @@ class TestProjectSubtasks(TestProjectCommon):
             ],
         })
 
-        task_count_with_subtasks_including_archived_in_project_goats = 6
+        task_count_with_subtasks_including_archived = 8
         task_count_in_project_pigs = self.project_pigs.task_count
         self.project_goats._compute_task_count()  # recompute without archived tasks and subtasks
         task_count_in_project_goats = self.project_goats.task_count
         project_goats_duplicated = self.project_goats.copy()
         self.project_pigs._compute_task_count()  # retrigger since a new task should be added in the project after the duplication of Project Goats
 
-        def subtask_in_project(tasks, project):
-            task_count = 0
-            for task in tasks:
-                if not task.project_id or task.project_id == project:
-                    task_count += 1 + subtask_in_project(task.child_ids, project)
-            return task_count
+        def dfs(task):
+            # ABGH: i used dfs to avoid visiting a task 2 times as it can be a direct task for the project and a subtask for another task like child 6
+            visited[task.id] = True
+            total_count = 1
+            for child_id in task.child_ids:
+                if child_id.id not in visited:
+                    total_count += dfs(child_id)
+            return total_count
 
-        tasks_copied_count = subtask_in_project(project_goats_duplicated.tasks, project_goats_duplicated)
+        visited = {}
+        tasks_copied_count = 0
+        for task in project_goats_duplicated.tasks:
+            if not task.id in visited:
+                tasks_copied_count += dfs(task)
 
         self.assertEqual(
             tasks_copied_count,
-            task_count_with_subtasks_including_archived_in_project_goats - 1,
+            task_count_with_subtasks_including_archived - 1,
             'The number of duplicated tasks (subtasks included) should be equal to the number of all tasks (with active subtasks included) of both projects, '
             'that is only the active subtasks are duplicated.')
         self.assertEqual(self.project_goats.task_count, task_count_in_project_goats, 'The number of tasks should be the same before and after the duplication of this project.')
@@ -254,6 +251,6 @@ class TestProjectSubtasks(TestProjectCommon):
                 child_subtask_form.name = 'Test Subtask 2'
                 self.assertFalse(child_subtask_form.project_id)
 
-        self.assertEqual(task.subtask_count, 2, "Parent task should have 2 children")
+        self.assertEqual(task.subtask_count, 1, "Parent task should have 1 children")
         task_2 = task.copy()
-        self.assertEqual(task_2.subtask_count, 2, "If the parent task is duplicated then the sub task should be copied")
+        self.assertEqual(task_2.subtask_count, 1, "If the parent task is duplicated then the sub task should be copied")
diff --git a/addons/project/tests/test_task_dependencies.py b/addons/project/tests/test_task_dependencies.py
index cb11d900c20..aa43c4f53c8 100644
--- a/addons/project/tests/test_task_dependencies.py
+++ b/addons/project/tests/test_task_dependencies.py
@@ -189,7 +189,6 @@ class TestTaskDependencies(TestProjectCommon):
 
     def test_duplicate_project_with_subtask_dependencies(self):
         self.project_goats.allow_task_dependencies = True
-        self.project_goats.allow_subtasks = True
         parent_task = self.env['project.task'].with_context({'mail_create_nolog': True}).create({
             'name': 'Parent Task',
             'project_id': self.project_goats.id,
diff --git a/addons/project/views/project_project_views.xml b/addons/project/views/project_project_views.xml
index 1349c35f5fc..86a20a1856a 100644
--- a/addons/project/views/project_project_views.xml
+++ b/addons/project/views/project_project_views.xml
@@ -112,11 +112,8 @@
                                 </group>
                             </group>
                             <group>
-                                <group name="group_tasks_managment" string="Tasks Management" col="1" class="row mt16 o_settings_container" groups="project.group_subtask_project,project.group_project_task_dependencies,project.group_project_milestone,project.group_project_recurring_tasks">
+                                <group name="group_tasks_managment" string="Tasks Management" col="1" class="row mt16 o_settings_container" groups="project.group_project_task_dependencies,project.group_project_milestone,project.group_project_recurring_tasks">
                                     <div>
-                                        <setting id="subtask_settings" help="Split your tasks to organize your work into sub-milestones" groups="project.group_subtask_project">
-                                            <field name="allow_subtasks"/>
-                                        </setting>
                                         <setting id="recurring_tasks_setting" help="Auto-generate tasks for regular activities" groups="project.group_project_recurring_tasks">
                                             <field name="allow_recurring_tasks"/>
                                         </setting>
@@ -463,16 +460,16 @@
                                                 type="object"
                                                 t-attf-title="#{record.milestone_count_reached.value} Milestones reached out of #{record.milestone_count.value}"
                                             >
-                                                <span class="fa fa-check-square-o me-1"/>
+                                                <span class="fa fa-flag me-1"/>
                                                 <t t-out="record.milestone_count_reached.value"/>/<t t-out="record.milestone_count.value"/>
                                             </a>
                                         </div>
                                         <field name="activity_ids" widget="kanban_activity"/>
                                     </div>
                                     <div class="oe_kanban_bottom_right">
+                                        <field name="user_id" widget="many2one_avatar_user" domain="[('share', '=', False)]" style="padding-right: 4px;"/>
                                         <field t-if="record.last_update_status.value &amp;&amp; widget.editable" name="last_update_status" widget="project_state_selection"/>
                                         <span t-if="record.last_update_status.value &amp;&amp; !widget.editable" t-att-class="'o_status_bubble mx-0 o_color_bubble_' + record.last_update_color.value" t-att-title="record.last_update_status.value"></span>
-                                        <field name="user_id" widget="many2one_avatar_user" domain="[('share', '=', False)]"/>
                                     </div>
                                 </div>
                             </div>
diff --git a/addons/project/views/project_sharing_project_task_views.xml b/addons/project/views/project_sharing_project_task_views.xml
index 20802099d53..e1a15756474 100644
--- a/addons/project/views/project_sharing_project_task_views.xml
+++ b/addons/project/views/project_sharing_project_task_views.xml
@@ -37,9 +37,9 @@
                 <field name="is_closed"/>
                 <field name="displayed_image_id"/>
                 <field name="active"/>
-                <field name="allow_subtasks"/>
-                <field name="child_text"/>
                 <field name="is_closed"/>
+                <field name="closed_subtask_count"/>
+                <field name="subtask_count"/>
                 <field name="allow_milestones" />
                 <field name="has_late_and_unreached_milestone"/>
                 <progressbar field="state" colors='{"1_done": "success", "03_approved": "success", "02_changes_requested": "warning", "1_canceled": "danger", "04_waiting_normal": "200", "01_in_progress": "200"}'/>
@@ -136,7 +136,7 @@
                         <field name="display_parent_task_button" invisible="1"/>
                         <button name="action_project_sharing_view_parent_task" type="object" class="oe_stat_button" icon="fa-tasks" string="Parent Task" attrs="{'invisible': [('display_parent_task_button', '=', False)]}"/>
                         <button name="action_project_sharing_open_subtasks" type="object" class="oe_stat_button" icon="fa-tasks"
-                            attrs="{'invisible' : ['|', '|', ('allow_subtasks', '=', False), ('id', '=', False), ('subtask_count', '=', 0)]}" context="{'default_user_ids': [(6, 0, [uid])]}">
+                            attrs="{'invisible' : ['|', ('id', '=', False), ('subtask_count', '=', 0)]}" context="{'default_user_ids': [(6, 0, [uid])]}">
                             <div class="o_field_widget o_stat_info">
                                 <span class="o_stat_value">
                                     <field name="subtask_count" widget="statinfo" nolabel="1"/>
@@ -174,7 +174,6 @@
                             <field name="parent_id" invisible="1" />
                             <field name="company_id" invisible="1" />
                             <field name="is_closed" invisible="1" />
-                            <field name="allow_subtasks" invisible="1" />
                             <field name="partner_id" options="{'no_open': True, 'no_create': True, 'no_edit': True}" attrs="{'invisible': [('project_id', '=', False)]}"/>
                             <field name="date_deadline" attrs="{'invisible': [('is_closed', '=', True)]}"/>
                         </group>
@@ -183,7 +182,7 @@
                         <page name="description_page" string="Description">
                             <field name="description" type="html" options="{'collaborative': true}"/>
                         </page>
-                        <page name="sub_tasks_page" string="Sub-tasks" attrs="{'invisible': [('allow_subtasks', '=', False)]}">
+                        <page name="sub_tasks_page" string="Sub-tasks">
                             <field name="child_ids" context="{'default_project_id': project_id, 'default_parent_id': id, 'default_partner_id': partner_id, 'form_view_ref' : 'project.project_sharing_project_task_view_form'}">
                                 <tree editable="bottom">
                                     <field name="project_id" invisible="1"/>
diff --git a/addons/project/views/project_task_views.xml b/addons/project/views/project_task_views.xml
index adb4224d562..e366662aefb 100644
--- a/addons/project/views/project_task_views.xml
+++ b/addons/project/views/project_task_views.xml
@@ -240,7 +240,6 @@
             <field eval="2" name="priority"/>
             <field name="arch" type="xml">
                 <form string="Task" class="o_form_project_tasks" js_class="project_task_form">
-                    <field name="allow_subtasks" invisible="1" />
                     <field name="is_closed" invisible="1" />
                     <field name="allow_recurring_tasks" invisible="1" />
                     <field name="recurrence_id" invisible="1" />
@@ -278,7 +277,7 @@
                         </button>
                         <!-- Dummy tag used to organize buttons -->
                         <span id="end_rating_buttons" invisible="1"/>
-                        <button name="action_open_parent_task" type="object" class="oe_stat_button" icon="fa-tasks" string="Parent Task" attrs="{'invisible': [('parent_id', '=', False)]}" groups="project.group_subtask_project"/>
+                        <button name="action_open_parent_task" type="object" class="oe_stat_button" icon="fa-tasks" string="Parent Task" attrs="{'invisible': [('parent_id', '=', False)]}"/>
                         <button name="action_recurring_tasks" type="object" attrs="{'invisible': ['|', ('active', '=', False), ('recurrence_id', '=', False)]}" class="oe_stat_button" icon="fa-repeat" groups="project.group_project_recurring_tasks">
                             <div class="o_field_widget o_stat_info">
                                 <span class="o_stat_value">
@@ -289,7 +288,7 @@
                             </div>
                         </button>
                         <button name="%(project_task_action_sub_task)d" type="action" class="oe_stat_button" icon="fa-tasks"
-                            attrs="{'invisible' : ['|', '|', ('allow_subtasks', '=', False), ('id', '=', False), ('subtask_count', '=', 0)]}" context="{'default_user_ids': user_ids}">
+                            attrs="{'invisible' : ['|', ('id', '=', False), ('subtask_count', '=', 0)]}" context="{'default_user_ids': user_ids}">
                             <div class="o_field_widget o_stat_info">
                                 <span class="o_stat_value">
                                     <field name="subtask_count" widget="statinfo" nolabel="1"/>
@@ -370,7 +369,7 @@
                         <page name="description_page" string="Description">
                             <field name="description" type="html" options="{'collaborative': true, 'resizable': false}" placeholder="Add details about this task..."/>
                         </page>
-                        <page name="sub_tasks_page" string="Sub-tasks" attrs="{'invisible': [('allow_subtasks', '=', False)]}">
+                        <page name="sub_tasks_page" string="Sub-tasks" attrs="{'invisible': [('is_private', '=', True)]}">
                             <field name="child_ids"
                                    context="{'default_user_ids': user_ids, 'default_parent_id': id,
                                     'default_partner_id': partner_id, 'default_milestone_id': allow_milestones and milestone_id}"
@@ -379,11 +378,11 @@
                                     <field name="is_closed" invisible="1"/>
                                     <field name="allow_milestones" invisible="1"/>
                                     <field name="sequence" widget="handle"/>
-                                    <field name="priority" widget="priority" optional="show" nolabel="1"/>
-                                    <field name="state" widget="project_task_state_selection" optional="show" nolabel="1" options="{'hide_label': 1}" />
+                                    <field name="priority" widget="priority" nolabel="1"/>
+                                    <field name="state" widget="project_task_state_selection" nolabel="1" options="{'hide_label': 1}" />
                                     <field name="id" optional="hide"/>
-                                    <field name="child_text" invisible="1"/>
-                                    <field name="allow_subtasks" invisible="1"/>
+                                    <field name="subtask_count" invisible="1"/>
+                                    <field name="closed_subtask_count" invisible="1"/>
                                     <field name="name" widget="name_with_subtask_count"/>
                                     <field name="project_id" string="Project" optional="hide" options="{'no_open': 1}"/>
                                     <field name="milestone_id"
@@ -396,13 +395,13 @@
                                     <field name="company_id" groups="base.group_multi_company" optional="hide"/>
                                     <field name="company_id" invisible="1"/>
                                     <field name="activity_ids" string="Next Activity" widget="list_activity" optional="hide"/>
-                                    <field name="date_deadline" attrs="{'invisible': [('is_closed', '=', True)]}" optional="show"/>
+                                    <field name="date_deadline" attrs="{'invisible': [('is_closed', '=', True)]}" optional="hide"/>
                                     <field name="tag_ids" widget="many2many_tags" options="{'color_field': 'color'}" optional="hide"/>
                                     <field name="rating_last_text" string="Rating" decoration-danger="rating_last_text == 'ko'"
                                         decoration-warning="rating_last_text == 'ok'" decoration-success="rating_last_text == 'top'"
                                         attrs="{'invisible': [('rating_last_text', '=', 'none')]}"
-                                        class="fw-bold" widget="badge" optional="hide"/>
-                                    <field name="stage_id" optional="show" context="{'default_project_id': project_id}" invisible="1"/>
+                                        class="fw-bold" widget="badge" optional="hide" invisible="1"/>
+                                    <field name="stage_id" optional="hide" context="{'default_project_id': project_id}"/>
                                     <button name="action_open_task" type="object" title="View Task" string="View Task" class="btn btn-link float-end"/>
                                 </tree>
                             </field>
@@ -414,10 +413,10 @@
                                     <field name="allow_milestones" invisible="1"/>
                                     <field name="parent_id" invisible="1" />
                                     <field name="is_closed" invisible="1" />
-                                    <field name="priority" widget="priority" optional="show" nolabel="1"/>
-                                    <field name="state" widget="project_task_state_selection" optional="show" nolabel="1"/>
-                                    <field name="child_text" invisible="1"/>
-                                    <field name="allow_subtasks" invisible="1"/>
+                                    <field name="priority" widget="priority" nolabel="1"/>
+                                    <field name="state" widget="project_task_state_selection" nolabel="1"/>
+                                    <field name="subtask_count" invisible="1"/>
+                                    <field name="closed_subtask_count" invisible="1"/>
                                     <field name="name" widget="name_with_subtask_count"/>
                                     <field name="id" optional="hide"/>
                                     <field name="project_id" optional="hide" options="{'no_open': 1}" />
@@ -427,18 +426,18 @@
                                         attrs="{'invisible': [('allow_milestones', '=', False)], 'column_invisible': [('parent.allow_milestones', '=', False)]}"
                                     />
                                     <field name="partner_id" optional="hide" widget="res_partner_many2one" attrs="{'invisible': [('project_id', '=', False)]}"/>
-                                    <field name="parent_id" optional="hide" attrs="{'invisible': [('allow_subtasks', '=', False)]}" groups="base.group_no_one"/>
+                                    <field name="parent_id" optional="hide" groups="base.group_no_one"/>
                                     <field name="user_ids" widget="many2many_avatar_user" optional="show" domain="[('share', '=', False), ('active', '=', True)]"/>
                                     <field name="company_id" optional="hide" groups="base.group_multi_company" />
                                     <field name="company_id" invisible="1"/>
                                     <field name="activity_ids" string="Next Activity" widget="list_activity" optional="hide"/>
-                                    <field name="date_deadline" attrs="{'invisible': [('is_closed', '=', True)]}" optional="show" />
+                                    <field name="date_deadline" attrs="{'invisible': [('is_closed', '=', True)]}" optional="hide" />
                                     <field name="tag_ids" widget="many2many_tags" options="{'color_field': 'color'}" optional="hide"/>
                                     <field name="rating_last_text" string="Rating" decoration-danger="rating_last_text == 'ko'"
                                         decoration-warning="rating_last_text == 'ok'" decoration-success="rating_last_text == 'top'"
                                         attrs="{'invisible': [('rating_last_text', '=', 'none')]}"
-                                        class="fw-bold" widget="badge" optional="hide"/>
-                                    <field name="stage_id" optional="show" invisible="1"/>
+                                        class="fw-bold" widget="badge" optional="hide" invisible="1"/>
+                                    <field name="stage_id" optional="hide"/>
                                     <button class="oe_link float-end" string="View Task" name="action_open_task" type="object"/>
                                 </tree>
                             </field>
@@ -446,7 +445,7 @@
                         <page name="extra_info" string="Extra Info" groups="base.group_no_one">
                             <group>
                                 <group>
-                                    <field name="parent_id" attrs="{'invisible': [('allow_subtasks', '=', False)]}" groups="base.group_no_one" context="{'search_view_ref' : 'project.view_task_search_form','search_default_project_id': project_id}"/>
+                                    <field name="parent_id" groups="base.group_no_one" context="{'search_view_ref' : 'project.view_task_search_form','search_default_project_id': project_id}"/>
                                     <field name="analytic_account_id" groups="analytic.group_analytic_accounting" context="{'default_partner_id': partner_id}"/>
                                     <field name="company_id" groups="base.group_multi_company" options="{'no_create': True}"/>
                                     <field name="sequence" groups="base.group_no_one"/>
@@ -531,8 +530,6 @@
                     <field name="activity_state"/>
                     <field name="rating_count"/>
                     <field name="rating_avg"/>
-                    <field name="allow_subtasks"/>
-                    <field name="child_text"/>
                     <field name="is_private"/>
                     <field name="rating_active"/>
                     <field name="has_late_and_unreached_milestone" />
@@ -541,6 +538,8 @@
                     <field name="company_id"/>
                     <field name="recurrence_id" />
                     <field name="subtask_count"/>
+                    <field name="closed_subtask_count"/>
+                    <field name="subtask_count"/>
                     <progressbar field="state" colors='{"1_done": "success", "03_approved": "success", "02_changes_requested": "warning", "1_canceled": "danger", "01_in_progress": "200", "04_waiting_normal": "200" }'/>
                     <templates>
                     <t t-name="kanban-menu" t-if="!selection_mode" groups="base.group_user">
@@ -553,24 +552,31 @@
                     <t t-name="kanban-box">
                         <div t-attf-class="{{!selection_mode ? 'oe_kanban_color_' + kanban_getcolor(record.color.raw_value) : ''}} oe_kanban_card oe_kanban_global_click">
                             <div class="oe_kanban_content">
-                                <div class="o_kanban_record_top">
-                                    <div class="o_kanban_record_headings">
+                                <div class="o_kanban_record_top" t-att-class="record.is_closed.raw_value ? 'opacity-50' : ''">
+                                    <div class="o_kanban_record_headings text-muted">
                                         <strong class="o_kanban_record_title">
-                                            <s t-if="!record.active.raw_value"><field name="name" widget="name_with_subtask_count"/></s>
-                                            <t t-else=""><field name="name" widget="name_with_subtask_count"/></t>
+                                            <s t-if="!record.active.raw_value">
+                                                <field name="name"/>
+                                            </s>
+                                            <t t-else="">
+                                                <field name="name"/>
+                                            </t>
                                         </strong>
-                                        <span invisible="context.get('default_project_id', False)"><br/><field name="project_id" widget="project_private_task" options="{'no_open': True}"/></span>
-                                        <span t-if="record.allow_milestones.raw_value and record.milestone_id.raw_value" t-attf-class="{{record.has_late_and_unreached_milestone.raw_value ? 'text-danger' : ''}}">
-                                            <br/>
+                                        <span t-if="record.parent_id.raw_value" invisible="context.get('default_parent_id', False)" style="display: block; margin-top: 4px;">
+                                            <field name="parent_id"/>
+                                        </span>
+                                        <span invisible="context.get('default_project_id', False)" style="display: block; margin-top: 4px;">
+                                            <field name="project_id" options="{'no_open': True}"/>
+                                        </span>
+                                        <t t-if="record.partner_id.value">
+                                            <field name="partner_id" style="display: block; margin-top: 4px;"/>
+                                        </t>
+                                        <span t-if="record.allow_milestones.raw_value and record.milestone_id.raw_value" t-att-class="record.has_late_and_unreached_milestone.raw_value ? 'text-danger' : ''" style="display: block; margin-top: 4px;">
                                             <field name="milestone_id" options="{'no_open': True}" />
                                         </span>
-                                        <br />
-                                        <t t-if="record.partner_id.value">
-                                            <field name="partner_id"/>
-                                        </t>
                                     </div>
                                 </div>
-                                <div class="o_kanban_record_body">
+                                <div class="o_kanban_record_body" t-att-class="record.is_closed.raw_value ? 'opacity-50' : 'text-muted'">
                                     <field name="tag_ids" widget="many2many_tags" options="{'color_field': 'color'}"/>
                                     <div t-if="record.date_deadline.raw_value" name="date_deadline" attrs="{'invisible': [('is_closed', '=', True)]}">
                                         <field name="date_deadline" widget="remaining_days"/>
@@ -580,22 +586,39 @@
                                     </div>
                                 </div>
                                 <div class="o_kanban_record_bottom" t-if="!selection_mode">
-                                    <div class="oe_kanban_bottom_left">
-                                        <field name="priority" widget="priority"/>
-                                        <field name="activity_ids" widget="kanban_activity"/>
+                                    <div class="oe_kanban_bottom_left" t-att-class="record.is_closed.raw_value ? 'opacity-50' : ''">
+                                        <field name="priority" widget="priority" style="margin-right: 5px;"/>
+                                        <field name="activity_ids" widget="kanban_activity" style="padding-top: 1.5px;"/>
                                         <b t-if="record.rating_active.raw_value and record.rating_count.raw_value &gt; 0" groups="project.group_project_rating">
-                                            <span style="font-weight:bold;" class="fa fa-fw mt4 fa-smile-o text-success" t-if="record.rating_avg.raw_value &gt;= 3.66" title="Average Rating: Satisfied" role="img" aria-label="Happy face"/>
-                                            <span style="font-weight:bold;" class="fa fa-fw mt4 fa-meh-o text-warning" t-elif="record.rating_avg.raw_value &gt;= 2.33" title="Average Rating: Okay" role="img" aria-label="Neutral face"/>
-                                            <span style="font-weight:bold;" class="fa fa-fw mt4 fa-frown-o text-danger" t-else="" title="Average Rating: Dissatisfied" role="img" aria-label="Sad face"/>
+                                            <span class="fa fa-fw fa-smile-o text-success rating_face" t-if="record.rating_avg.raw_value &gt;= 3.66" title="Average Rating: Satisfied" role="img" aria-label="Happy face"/>
+                                            <span class="fa fa-fw fa-meh-o text-warning rating_face" t-elif="record.rating_avg.raw_value &gt;= 2.33" title="Average Rating: Okay" role="img" aria-label="Neutral face"/>
+                                            <span class="fa fa-fw fa-frown-o text-danger rating_face" t-else="" title="Average Rating: Dissatisfied" role="img" aria-label="Sad face"/>
                                         </b>
-                                        <a t-if="record.subtask_count.raw_value and record.allow_subtasks.raw_value" class="subtask_list_button" title="See Subtasks" style="padding: 0px 5px 0px 0px; box-sizing: border-box; font-size: 20px;"/>
+                                        <a t-if="!record.project_id.raw_value" class="text-muted" style="font-size: 17px; padding-top: 1.5px;">
+                                            <i title="Private Task" class="fa fa-lock"/>
+                                        </a>
+                                        <t t-if="!record.is_private.raw_value and record.subtask_count.raw_value">
+                                            <div t-attf-class="{{record.subtask_count.value &gt; record.closed_subtask_count.value}}"></div>
+                                            <a t-if="!record.is_private.raw_value and record.subtask_count.raw_value and record.subtask_count.value &gt; record.closed_subtask_count.value" class="text-muted">
+                                                <span t-attf-title="{{ record.closed_subtask_count.value }} sub-tasks closed out of {{ record.subtask_count.value }}" class="subtask_list_button fa fa-check-square-o me-1"/>
+                                                <t t-out="record.closed_subtask_count.value"/>/<t t-out="record.subtask_count.value"/>
+                                            </a>
+                                            <div t-else="" class="text-muted">
+                                                <span t-attf-title="{{ record.closed_subtask_count.value }} sub-tasks closed out of {{ record.subtask_count.value }}" class="fa fa-check-square-o me-1"/>
+                                                <t t-out="record.closed_subtask_count.value"/>/<t t-out="record.subtask_count.value"/>
+                                            </div>
+                                        </t>
                                     </div>
                                     <div class="oe_kanban_bottom_right" t-if="!selection_mode">
+                                        <div  t-att-class="record.is_closed.raw_value ? 'opacity-50' : ''">
+                                            <field name="user_ids" widget="many2many_avatar_user" domain="[('share', '=', False)]"/>
+                                        </div>
                                         <field name="state" widget="project_task_state_selection" options="{'hide_label': 1, 'is_toggle_mode': false}"/>
-                                        <field name="user_ids" widget="many2many_avatar_user" domain="[('share', '=', False)]"/>
                                     </div>
                                 </div>
-                                <div class="kanban_bottom_subtasks_section"/>
+                                <t t-if="!record.is_private.raw_value and record.subtask_count.raw_value and record.subtask_count.value &gt; record.closed_subtask_count.value">
+                                    <div class="kanban_bottom_subtasks_section"/>
+                                </t>
                             </div>
                             <div class="clearfix"></div>
                         </div>
@@ -616,11 +639,11 @@
                     <field name="is_private" invisible="1" />
                     <field name="sequence" invisible="1" readonly="1"/>
                     <field name="allow_milestones" invisible="1"/>
+                    <field name="subtask_count" invisible="1"/>
+                    <field name="closed_subtask_count" invisible="1"/>
                     <field name="id" optional="hide"/>
-                    <field name="priority" widget="priority" optional="show" nolabel="1"/>
-                    <field name="state" widget="project_task_state_selection" optional="show" nolabel="1"  options="{'hide_label': 1, 'is_toggle_mode': false}"/>
-                    <field name="child_text" invisible="1"/>
-                    <field name="allow_subtasks" invisible="1"/>
+                    <field name="priority" widget="priority" nolabel="1"/>
+                    <field name="state" widget="project_task_state_selection" nolabel="1" options="{'hide_label': 1, 'is_toggle_mode': false}"/>
                     <field name="name" string="Title" widget="name_with_subtask_count"/>
                     <field name="project_id" widget="project_private_task" optional="show" readonly="1" options="{'no_open': 1}" invisible="context.get('default_project_id')"/>
                     <field name="milestone_id" attrs="{'invisible': [('allow_milestones', '=', False)]}" context="{'default_project_id': project_id}" groups="project.group_project_milestone" optional="hide"/>
@@ -629,7 +652,7 @@
                     <field name="company_id" groups="base.group_multi_company" optional="show" invisible="context.get('default_project_id')"/>
                     <field name="date_deadline" optional="hide" widget="remaining_days" attrs="{'invisible': [('is_closed', '=', True)]}"/>
                     <field name="tag_ids" widget="many2many_tags" options="{'color_field': 'color'}" optional="show" context="{'project_id': project_id}"/>
-                    <field name="stage_id" invisible="context.get('set_visible',False)" optional="show" readonly="not context.get('default_project_id')"/>
+                    <field name="stage_id" invisible="context.get('set_visible',False)" optional="show"/>
                 </tree>
             </field>
         </record>
@@ -658,7 +681,7 @@
                     <field name="recurrence_id" invisible="1" />
                 </tree>
                 <xpath expr="//field[@name='partner_id']" position="after">
-                    <field name="parent_id" optional="hide" context="{'search_view_ref' : 'project.view_task_search_form', 'search_default_project_id': project_id}" attrs="{'invisible': [('allow_subtasks', '=', False)]}" groups="base.group_no_one"/>
+                    <field name="parent_id" optional="hide" context="{'search_view_ref': 'project.view_task_search_form', 'search_default_project_id': project_id}" groups="base.group_no_one"/>
                 </xpath>
             </field>
         </record>
@@ -809,9 +832,6 @@
                 <tree position="attributes">
                     <attribute name="default_group_by">personal_stage_type_ids</attribute>
                 </tree>
-                <field name="stage_id" position="replace">
-                    <field name="stage_display" optional="show" string="Stage"/>
-                </field>
             </field>
         </record>
 
@@ -827,9 +847,6 @@
                 <field name="project_id" position="attributes">
                     <attribute name="invisible">0</attribute>
                 </field>
-                <field name="stage_id" position="replace">
-                    <field name="stage_display" optional="show" string="Stage"/>
-                </field>
             </field>
         </record>
 
diff --git a/addons/project/views/res_config_settings_views.xml b/addons/project/views/res_config_settings_views.xml
index 27d39b43f8c..cceae04851b 100644
--- a/addons/project/views/res_config_settings_views.xml
+++ b/addons/project/views/res_config_settings_views.xml
@@ -9,9 +9,6 @@
                 <xpath expr="//form" position="inside">
                     <app data-string="Project" string="Project" name="project" groups="project.group_project_manager">
                         <block title="Tasks Management" id="tasks_management">
-                            <setting help="Split your tasks to organize your work into sub-milestones">
-                                <field name="group_subtask_project"/>
-                            </setting>
                             <setting id="recurring_tasks_setting" help="Auto-generate tasks for regular activities">
                                 <field name="group_project_recurring_tasks"/>
                             </setting>
diff --git a/addons/sale_timesheet/views/project_task_views.xml b/addons/sale_timesheet/views/project_task_views.xml
index 682037544ba..7ca5840394f 100644
--- a/addons/sale_timesheet/views/project_task_views.xml
+++ b/addons/sale_timesheet/views/project_task_views.xml
@@ -65,7 +65,7 @@
                    <a name="action_view_all_rating" type="object">
                     Customer Ratings
                     </a>
-                </div> 
+                </div>
             </xpath>
         </field>
     </record>
@@ -87,27 +87,6 @@
         </field>
     </record>
 
-        <record id="view_sale_service_inherit_form2" model="ir.ui.view">
-            <field name="name">sale.service.form.view.inherit</field>
-            <field name="model">project.task</field>
-            <field name="inherit_id" ref="hr_timesheet.view_task_form2_inherited"/>
-            <field name="arch" type="xml">
-                <xpath expr="//field[@name='child_ids']/tree//field[@name='remaining_hours']" position="after">
-                    <field name="sale_line_id" invisible="1"/>
-                    <field name="remaining_hours_available" invisible="1"/>
-                    <field name="remaining_hours_so" widget="timesheet_uom" optional="hide" groups="base.group_user"
-                        attrs="{'invisible': ['|', ('sale_line_id', '=', False), ('remaining_hours_available', '=', False)]}"/>
-                </xpath>
-                <xpath expr="//field[@name='depend_on_ids']/tree//field[@name='remaining_hours']" position="after">
-                    <field name="sale_line_id" invisible="1"/>
-                    <field name="remaining_hours_available" invisible="1"/>
-                    <field name="remaining_hours_so" widget="timesheet_uom" optional="hide" groups="base.group_user"
-                        attrs="{'invisible': ['|', ('sale_line_id', '=', False), ('remaining_hours_available', '=', False)]}"/>
-                </xpath>
-
-            </field>
-        </record>
-
         <record id="view_task_tree2_inherited" model="ir.ui.view">
             <field name="name">project.task.tree.inherited</field>
             <field name="model">project.task</field>