Hi, I have the latest iOS15 Beta 4 on my iPad Pro 12.9” M1 and Dorico looks great. It is wonderful using the Ravenscroft 275 piano with this app. It seems IOS15 is very different with regards to how it works with AUv3
Dorico often crashes with IOS15 and you can not change instruments in iSymphonic or other AUv3 apps. You have to open GarageBand as well to activate AUv3 in Dorico as by default you get none. After opening GarageBand the external modules come up in the play section.
IO15 is due in the fall and so hopefully at the bugs will be fixed. I can not go back to IOS14 and have a subscription so looking forward to using these features
I was able to add instruments for a full score in playback mode however mostly the same as can not be changed.