hello @RafaŁ-Buchner, this is a great summary and a very valuable test case. please let us know how it goes! something I wish I knew when I was upgrading to RF3: you can use different folders for your RF3 and RF1 extensions. this allows you to start fresh in RF3 without messing up your current RF1 extensions setup. (the extensions folder can be configured in Preferences > Extensions) another place to keep an eye for error messages and tracebacks is the log file. (use the keyboard shortcut ⌃ ⌘ ⌥ O to jump to it in Finder) setting warningsLevel to always is good for detecting problems, but I would recommend setting it to ignore while working. (printing a lot of deprecation warnings to the Output Window might slow things down a bit) ps. most extensions have been upgraded to RF3 by now, so switching to RF3 today is smoother than it was 1 year ago. (those who tried and gave up are encouraged to try again :)