When a user changes their login name (e.g. because they got married), we would like to preserve that user's old revision history. (Mentions and watches would also be nice, but not as important. And preserving their old Personal Space would also be preferable, although currently the workaround is to create a new Personal Space, and move the contents of their old Personal Space into it.)
According to Confluence 5.3 Release Notes, if a user's name changes in an external LDAP directory, then "Confluence will automatically detect the renamed user." (It does not say how it does this – i.e. how does it know the old and new names in the LDAP directory are related?)
Specifically, in the Mentions and page history section under Notes at the bottom of the page, "Any user mentions in current pages will automatically reflect the user's new username, but any mentions in page versions created prior to Confluence 5.3 will include the user's old username."
However, this does not appear to be true. Even for page revisions (versions) created after we upgraded from Confluence 5.1 to 5.5 a year ago, the user's revisions appear under their old login name (now an "Unknown user").
In other words, the new LDAP account appears as if it is a completely brand new user, and the old account is simply gone from the directory (an "Unknown user"). There appears to be no connection whatsoever between the old and new accounts.
Update: Perhaps a rephrasing might help. The ability to Change usernames came in Confluence 5.3, and is described in the Confluence 5.3 Release Notes. For instances like ours, where we manage our users in an external LDAP directory, all it says is that "Confluence will detect the changes." How is that supposed to work? Is there something special we need to do in that LDAP directory to associate the old username with the new one?