(As this question might come up with others, I thought I answer it right now).
Answer: Generally No!
Explanation: All Events, Models, Stratagems and a whole bunch of other information are copied from the Scenario File (randomgame.se1) into the savegame when the planet is created. They are as integral to the savegame, as the worldmap you play on, the techlevel you started on or any other part of the game setup.
This applies to official patches as well - one of the most common marker in patchnotes is "* requires a new savegame to take effet", as this is actually a change to the scenario file itself.
These are on top of the usual candidates, like world creation options (which naturally can not have a retroactive effect).
Under Reports, the Empire Dashboard lists the gameversion that was used to create the savegame, just to avoid mistakes in this regard. As savegame that was created a few versions ago can add a lot of old bugs into the game.
It is actually easier to list the things that do not require a new savegame. They include:
- purely graphical or audio mods, as long as they just overwrite the vanilla files
- a lot of the patchnotes deal with the actuall code. These changes do have effect in savegames created in older versions
- despite this, some sweeping code changes also require a savegame from a new version, or a opt-in during world creation. This is done by Vic purely for player convenience.
< Message edited by zgrssd -- 6/2/2021 8:05:54 PM >