Hi,
We are currently having our game out to alpha tester who have played it some and therefore have an old savegame. I recently updated the structure of the savegame and when the game tries to load it a fatal crash occurs.
How do i handle checking the version of a savegame, so i can reset it if it is an older version?
Any other tips on how to handle data migration between versions are welcome to 
You can save the version of your game with the old save game. Then you can check if you have to do any additional work if the player loads an old save game.
It will not crash by trying to load the version if other pieces of the savegame has been changed?
It worked. Right now i have a Map of Integers stored in my save game and i put a version number among them. It seems it is possible to load everthing from a save game that has not changed.