Putting everything together, from a non coder point of view: most dev builds up to now used their own install path and a different user profile path (at least on Linux), so the problem is not to do that but IF AOO 3.4 *need* to do that.
Options: 1- Use same install path and same user profile path than 3.3. PROS: consistent with OOo 3.x behaviour (with x > 1: as someone commented before, 3.0 did not override 2.4 user profile). CONS: the inevitable deletion of user installed extensions could left extension related menu entries that cannot be deleted, with the very negative point that downgrading to 3.3 will not fix the problem. This have the potential to provide a negative image to the project: normal users will not understand what's going on. 2- Use same install path but different user profile path. PROS: if user downgrade, everything will be as before. CONS: a downgrade could be needed to finish that urgent work (yes, there are many users that upgrade in the middle of an important work...) 3- Use a new install path and a new user profile path. PROS: both programs running safely side by side, giving the user time to migrate the work slowly and without problems. CONS: disk space? I prefer option 3, but have no problem if other solutions are used instead. Regards Ricardo