I started a new project last night using 20R2.1. I saved it to a new folder as a binary project (I hadn’t logged in for my license on the system). I left Xojo running and continued working this morning. I then attempted to save with CMD-S and received the following popup dialog:
Do you have default project templates by chance? If you created these with an older version, when you save after creating a new project with the newer version you can get this warning.