Not that much: File: rom/exec/openlibrary.crom/exec/opendevice.c Fix: SMP race / deadlock: Replaces EXEC_UNLOCK_LIST with EXEC_UNLOCK_LIST_AND_PERMIT. Prevents deadlocks on multicore systems (RPi4/5, x86 SMP). File: rom/graphics/setfont.c Fix: NULL pointer crash: Guards against a crash on SetFont(rp, NULL) and restores the DefaultFont in a standards-compliant way. File: workbench/c/Shell/Shell.c Fix: Background shell fix: Prevents cli_Background from being overwritten by IsInteractive() in background processes (e.g. via RunCommand). File: workbench/devs/AHI/Drivers/RPiI2S/ Fix: I2S audio DAC HATs: AHI driver for external I2S sound cards (HiFiBerry DAC, IQaudIO, PCM5102A, MAX98357A) on RPi4 (GPIO 18-21) and RPi5 (RP1 I2S).