I discovered this problem when renaming a user account in Zimbra 6.07
User firstname.lastname@example.org got married and needed to be renamed email@example.com
The rename is easily done in the ZAC, however when the user sends or replies to an email it is still being sent from firstname.lastname@example.org
Fiddling around with personas in Outlook or webmail did not fix this problem.
Personas worked when i set it to email@example.com or firstname.lastname@example.org but not jane.black@mydomain even when i created a persona with jane.black as a persona.
The only way i could fix this was to use the zmprov command.
zmprov ga email@example.com | grep -i canonical
zmprov ma firstname.lastname@example.org zimbraMailCanonicalAddress email@example.com
In summary 6.07 removed the canonical address from the ZAC however renaming user accounts from the ZAC does not rename the canonical address.
Headaches for me but hopefully useful to know for others.