Updated migration guide!
With the preview.15 and preview.16 updates, here come the new details you'll need to know to both move between package versions and from package to 2021.2![;)]( "Wink ;)")
NOTE: You need both UI Toolkit and UI Builder packages to be on version preview.15 or preview.16 if you want to use both, as they're not compatible with other versions. We highly recommend using preview.16 due to important fixes.
Package version migration...
UI Toolkit migration guide
With the preview.15 and preview.16 updates, here come the new details you'll need to know to both move between package versions and from package to 2021.2
NOTE: You need both UI Toolkit and UI Builder packages to be on version preview.15 or preview.16 if you want to use both, as they're not compatible with other versions. We highly recommend using preview.16 due to important fixes.
Package version migration...
UI Toolkit migration guide