I use svn (subversion) for versioncontrol of all my projectfiles. For easypc it is not of much extra use except it being sort of a logbook. The files are binary for my versioncontrol, so I cannot diff them.
But using svn for me has the advantage all my designfiles are in one database that has a proper backup procedure.
I believe since v11 easypc has some form of versioncontrol too, but I have not played with it yet.
The feature in Easy-PC is a 'cyclic backup' rather than any real version control, this just ensures that when you save designs it maintains a copy of the last three saves as a backup.
So it lets you go back to a slightly older copy if you change your mind about a modification you've just made, but as the third oldest copy gets overwritten on every save as they all move down one step, it isn't going to be much help as a version system or long-term backup.
The other option for Easy-PC if you're using projects is to periodically save each project to a new version. That way you've got a series of projects which could include a version as part of the filename giving you a traceable history. A sort of poor man's tracker...