I hit a similar issue right yesterday: auval was failing with message
“ERROR: Component Version mismatch: Res Vers = 0x10102, Comp Vers = 0x10103”
In my case, I solved it by adding a pre-build script that does a
touch include_juce_audio_plugin_client_AU.r
inside the JuceLibraryCode folder.
Unfortunately, the Rez command (at least in Xcode 8, which I’m using), only reacts to the update of the file it is Rezzing, NOT of those that said file #includes, recursively.
This means that updating “AppConfig.h” with the new version number seems to be not enough, touching the main ‘.r’ file seemed to be the only viable choice