I have a number of projects to update, and they are all have .rbp extension. A Xojo support person said that .rbp are old files and sounded like .xojo_binary_project is newer. Should I save them in .xojo_binary_project then?
If your license allows it, you should save in a text format (Xojo Project or Xojo XML Project).
If you have a Lite license and plan to continue to use the Xojo IDE with these projects, it may be to your benefit to use the new format at the very minimum to tell it apart from your original project.
If you are using a newer IDE, the newer file format will be automatically saved into the file even if it has the old filename. There’s no need to do a Save As.
Just remember that an older IDE won’t understand newer flags like Dark Mode, HiDPI, ARM architecture, and so these settings would be lost if you re-save from the older IDE.