Sorry, that was a poor use of English on my part. As Sam said, it will be available in 5.0 - the important information in bugzilla is the 'Target Milestone'.
I've reread the bug in bugzilla and only now fully understand what is all means, so the behaviour discussed in the comments will work in release 5 (Franklin). Looking at the previous releases it will be out soon (historically Zimbra has never been at such a high digit after the point until now). Can you or someone else speculate when version 5 will be out? (or do you use fixed version incrementation dates like openbsd does for example).
if only that was in european notation (dd/mm/yyyy)it shows a target release date of 7/2/2007