I have some 'older' hardware that requires I install 21.0.0.215 to run the associated software Circut Craft Room. Cricut have sent me a work round involving uninstalling and reinstalling from your archived version 21. The software downloads but will not open, I'm trying to install on a Mac note book running 10.12.1. Cricut say I cannot be uninstalling correctly and to contact Adobe for advice. This is the trouble shooting page circuit sent me to with the method to use to fix
Cricut Craft Room Troubleshooting | Cricut Help Center
The error message I get when trying to install the new hardware mentioned is firmware issue. Not the error that they mention in the link, I have not had it installed previously but have since tried and succeeded in installing onto a Windows machine albeit I had to downgrade the adobe air to version 21.
Yours hopefully
Helen