[type0]

It is if you own copyright for that code, then you can re-license. It seems Canonical didn't ask the permission of contributors that haven't signed their CLA, so Canonical have no right to change the license for that code

> However, they need to make it clear which parts are under Apache 2.

The only thing they needed to do is to add the statement that parts of the code that were written before LXD 5.20 remain Apache 2.0