Saving will increase the minimum version of the IDE required to open this project.
All this is saying is that the IDE version will now come in line with the version of Xojo you are using.
Most projects are marked internally as allowing Xojo2007 to edit the project.
But once you add an image (the PNG you mentioned) it now requires that the IDE supports Imagesets , which 2007 did not.
Therefore, this is NOTHING to worry about, and in my opinion that message does nothing but cause undue concern on the part of the developer… I know it did for me for a while
Pretty sure that warning about opening with newer/older versions were inserted as a result of user requests for such warnings
Some older IDE’s do not check these things at all since they didnt exist when those versions were created
And so opening with one of those old IDE’s may silently break your project when you open it, make changes and save
If Xojo added more stuff to a Xojo project that an old IDE cannot understand the warning still applies
BUT IDE’s that do know about these settings will warn you when you try to open a project they do not know how to open
