Numbering of statements is not anymore automated, sequence of the journal is now only used for the numbering of account.move (for consistancy with payments). Name of statements now appears as 'reference'.
Cancelling of a statement line keeps in memory the old move's name to reuse it in the same fashion as for account.invoice (avoiding gaps in numbering).
Cancelling of a payment now keeps in memory the old move's name to reuse it in the same fashion as for account.invoice (avoiding gaps in numbering)