arnocazin, it really depends on what you're using. From what I've know, the current package doesn't even work on the latest alpha, which doesn't come as a surprise, looking at the differences since the (my) latest ox release.
If you're simply installing ox as described in the various howto's on open-xchange.org, it depends on the changes. If any files requiring compilation (for example .java) have been changed, you need to recompile those. You may offcourse replace any files which need to be updated instead of removing and replacing all.
A bigger problem is when they've updated the ldap schema, since all ldap entries need to be updated, for which I'm not sure how to explain an easy way. It really gets specific there (meaning I would need to know what changed to help you out).
The same sort of goes for postgresql.
All in all, best you look up the changes (as in file-based, not as in change-log) and go from there, either asking help here or using a method above.
Keep in mind that any alpha's and ox packages released up to now have been and still are for testing purposes only.
I can't tell you if something will break after updating, and you shouldn't be using a setup on which that matters.