Hello. I’m running StudioMux v. 5516 on iPadOS 14.7.1, StudioMux Instrument v. 5093 on Bitwig 3.3.10 (Windows 10 v. 20H2). AUv3 instruments loaded into StudioMux sound out of tune, off by about a half-step. IAA instruments don’t seem to be affected by this.
On the other hand, neither IAA or AUv3 respond to MIDI cc’s or pitch bend sent from Windows to the iPad through Studiomux (note-on and note-off messages are fine).
One more question, are you dropping support of VST2? The old VST DLLs don’t seem to work with this version of the server (or with the old server and the recently update iPad app, for that matter).