Is it possible to use ARM compiler version 4.9.3 to compile code for newer ARM MCUs such as nRF52840 or STM32WB series?

Do old ARM compilers support compilation for newer ARM MCUs? How to actually check it?
I am limited to usage of ARM compiler version 4.9.3. I want to know if I can use the same compiler to create binaries for new MCUs for example nRF52840 or STM32WB series.

From what I know there shouldn't be any issues, but maybe I am missing something.

STM32WB is dual core Cortex-M0+ and Cortex-M4, while nRF52840 is Cortex M4. They are not particularly "new", the age of the device is irrelevant, it is when the core (or more specifically when the architecture version the core uses) was introduced that is key. And whether that is supported by the compiler. That should be clear from the documentation and the available architecture specification command line switches.

• M0+ is Armv6-M
• M4 is Armv7E-M

If you are referring to gnu-arm rather the ARM's own legacy ARM Compiler ARMCC (for which there is no such version as 4.9.3 - 4.1 was the last v4, and v5.x was the last ARMCC - v6 is based on LLVM/clang). Then yes, those architectures are supported - see documentation at https://gcc.gnu.org/onlinedocs/gcc-4.9.4/gcc/ARM-Options.html#ARM-Options, in particular the -march and -mtune options - they allow you to specify the architecture or the core respectively - you don't need both.

If you are using a toolchain that provides device/manufacturer specific support with libraries, linker scripts, start-up code and debugger support for peripherals for example, you may not get all (or any) of that and will have to adapt existing support for similar devices or create your own.