If you are eager to use the AVR-GCC15.1 toolchain, it can now be made available by installing (an experimental fork of) a board package, namely the Arduino AVR Boards. You only have to add the following Additional Boards Manager URLs in the Preferences dialog:
https://felias-fogg.github.io/ArduinoCore-avr/package_GCC15_ArduinoCore-avr_index.json
After that, update the package to the most recent version (which will have a '-gcc15x' suffix). And if you are really adventurous, you can even select one of the more recent C++ language variants instead of c++11, which is the currently enabled version. This can be accomplished by using the new #pragma arduino directive first introduced in TinyCore. Add, for example, the following line to your sketch file:
#pragma arduino cpp_flags -std=c++23
Alternatively, if you want to change things globally, you can add platform.local.txt to the board package folder with the appropriate settings.
Some caveats:
- The new toolchain itself is much bigger than the original 7.3.0 one.
- I used the toolchain set provided by Microchip, which unfortunately does not contain a 32-bit Windows version, which means that Windows users cannot use the IDE 1.8.19 to run the toolchain.
- There is also no ARM64 Linux version.
If there is high demand, I could be convinced to generate the 32bit Window and ARM64 Linux versions.
On the positive side:
- For the Mac, there are universal binaries, i.e., you do not need Rosetta any longer.
- In the 15.1 toolchain, a number of bugs, in particular in connection with debugging, have been fixed.
- The board packages are also debug-enabled.
- If things do not work out, you always can easily downgrade to the board package versions with the original 7.3.0 toolchain.