Updates have broken my system

This morning I updated the OS on my iMAC to macOS Big Sur Version 11.0.1, along with this Xcode to Version 12.2 (12B45b). Before these updates I was using Qt Creator 4.13.2 Based on Qt 5.15.1, I could build projects without issue, however since the updates I can no longer build. I've cleaned the build folders, run make again, but this doesn't help the error I'm getting wither project I build is:

Compile Output:

12:51:26: Running steps for project XMLMPAM...

12:51:26: Starting: "/usr/bin/make" clean -j8

/Users/simonplatten/Qt/5.15.1/clang_64/mkspecs/features/mac/sdk.mk:22: *** ^. Stop.

The platform SDK has been changed from version 10.15.6 to version 11.0.

This requires a fresh build. Please wipe the build directory completely,

including any .qmake.stash and .qmake.cache files generated by qmake.

12:51:26: The process "/usr/bin/make" exited with code 2.

12:51:26: Starting: "/Users/simonplatten/Qt/5.15.1/clang_64/bin/qmake" /Users/simonplatten/XMLMPAM/XMLMPAM.pro -spec macx-clang CONFIG+=debug CONFIG+=x86_64 CONFIG-=qml_debug CONFIG-=qtquickcompiler

12:51:26: The process "/Users/simonplatten/Qt/5.15.1/clang_64/bin/qmake" exited normally.

12:51:26: Starting: "/usr/bin/make" -f /Users/simonplatten/XMLMPAM/build-XMLMPAM-Desktop_Qt_5_15_1_clang_64bit-Debug/Makefile qmake_all

/Users/simonplatten/Qt/5.15.1/clang_64/mkspecs/features/mac/sdk.mk:22: *** ^. Stop.

The platform SDK has been changed from version 10.15.6 to version 11.0.

This requires a fresh build. Please wipe the build directory completely,

including any .qmake.stash and .qmake.cache files generated by qmake.

12:51:27: The process "/usr/bin/make" exited with code 2.

Error while building/deploying project XMLMPAM (kit: Desktop Qt 5.15.1 clang 64bit)

When executing step "qmake"

12:51:27: Elapsed time: 00:01.

Issues:

/Users/simonplatten/Qt/5.15.1/clang_64/mkspecs/features/mac/sdk.mk:22: warning: *** ^. Stop.

Now I'm stuck and cannot progress any further.