Missions with no objectives
Before 4.00 Beta 3 all missions in a vanilla game were ensured to also specify a mission objective. While it was possible already before to create missions by mods without an objective, that case was not used in a vanilla game.
Hence, a modder could rely on the fact that for a valid mission, he could just call GetMissionIDObjective() and retrieve some appropriate data (at least in a vanilla game).
As of 4.00 Beta 3, you'd now check whether a mission has an objective before making the calls to retrieve the objective details. To help with that some functions were added/extended:
Dropped support for multiple holomaps
Before 4.00 Beta 3 it was possible to create multiple holomaps. However, the implementation was suffering some flaws. Due to some other changes done during 4.00 these flaws now surfaced in that in certain error handling cases the once retrieved holomaps no longer cleaned up correctly.
To resolve this, we dropped the support for multiple holomaps in 4.00 Beta 3. This means that any call to AddHoloMap() will return the same shared holomap. We are not aware of any mod combination which would rely on multiple holomaps being used. If you have such a mod or are aware of an actual combination of mods which require this set up, please leave a comment here.