It used to return utf-8 data but was brittle in the conversion, and would fail downstream if the calling code did not pay attention to handle utf-8 data properly. Returning unicode forces callers to auto-cast to unicode for any string operation, saving potential trouble later. From the addons that currently call toxml(), none use it in a manner that would fail in case unicode data is returned, so we should be on the safe side there too. lp bug: https://launchpad.net/bugs/695960 fixed bzr revid: odo@openerp.com-20110117184444-mxjeneuoa0r5a85n