In v8.1.0 the only choices under Project Theme → Select Template are related to “Bootswatches”. Previously (under v7.1.2) there were many more choices, including the theme I had chosen for my project. So could we call this a “breaking change”?
Yes, this is because v7.1.2 uses bootstrap 4 and v8.1.0 uses bootstrap 5. Release Notes | Documentation (radsystems.io)
I read the release notes prior to upgrading from 7.1.2
There is no mention of losing any existing features, or breaking changes.
So in effect the new version is a new product offering, not an upgrade.