Making a patch compatible with old save files

Sorry if I should make a new thread for this, but I've run into this recently. Will this problem crop up for players if I release a patch? If so, how do I make a patch/update that doesn't negatively effect those who have a previous save?

@woootbm yes, if you add a plugin that makes old savefiles incompatible then the players will need to start new games.
and no, you can't prevent that - only the plugin writer could do that by writing the plugin in a way that it doesn't disrupt old savefiles.
And most plugin writers don't care about that because 1) it will require a more complex handling of the savefiles that most of them don't know how, and 2) it is usually considered best that players only get the finished game unless they're participating in playtests (where they should expect that).

Even big companies have sometimes patches that invalidate the saves and require a new game even in their professional engines and with dozens of professional people knowing exactly what they're doing - with RMs you'll have that much more often because you don't have the resources needed to prevent that.

and yes, you should have made a new topic instead of hijacking this one.

@Andar Ah, well, whoops. It's still mostly on topic. If you ask me, the rules around here are insanely strict. Like, having my question on here means someone Google-searching the topic on a broader scale might find that info here rather than digging through 10 similar topics.

Anyway, if you don't mind, I didn't run into the problem that you are guessing at. What I'm running into is that certain save data (specifically the states of events) gets reset between saves. It seems like this is some kind of feature when using playtest. IE, RPM is refreshing all events in case they were changed so you can test them. But I don't think it affects live builds. I have done everything I need to in order to version-test my game, so I get confused when things aren't behaving as they "should."

completely wrong - your question was absolutely and completely off-topic.
This is the support area where specific questions to solve problems are asked, and your question had absolutely nothing to do with the OP or his problem and didn't help him in any way, it was to help only yourself in a topic that was dedicated to helping someone else.
And on this board everything should be strictly on topic, so that reading the title of a topic tells you what could be inside.

@woootbm As your query was off-topic and hi-jacking an existing thread, I have split yours and Andar's posts into a separate thread.

@Kes Uh, that's fine. So long as I don't get burned at the stake for "double-posting" since I already made my own post a few minutes before you chopped up this one :kaoswt2:

It would probably be good if you can explain exactly what is happening, possibly in a step by step manner. And also what you actually want to do :)