I'm trying to figure out why some parts keep having new versions created when checking out and checking right back in. Sometimes, an undo checkout occurs (as I would expect it to with no changes to the file), but sometimes a new version gets created and I'm not sure what's causing PDM to think a new version should be created.
If a referencing parent file changes versions, would that cause a version change to the child part? I tried testing this out specifically and the answer was a no, but that's the only reason why I can think of for why the new versions to my real parts are getting created.
for option 1) no. If you upgrade solidworks, everytime you open a file that is of an older format, it will automatically convert it to the current solidworks version. So for example, if you migrated in files to the vault that were of an older format, the next time the user opens the file with solidworks, it will convert it. Chances are you will be prompted to save a "read-only" file. If no one ever says yes to this... it will always ask you.
for option 2) i don't think so, but this may this depends on your settings. When a file is opened, one of the first things it does it try to find it's references. Regardless of check in our check out. Even changing printer settings will trigger the file as changed.
for option 3) like option 2, when you open a drawing it will make sure that everything is correct with it's views and references. If it finds any differences, it will flag the file as changed and request that you save changes.