Invalid syntax with MEM_CAPACITY = 640_000

When downloading the code and then doing the Quickstart, instead of working, it prints out:
File "porth.py", line 18
MEM_CAPACITY = 640_000 # should be enough for everyone
^
SyntaxError: invalid syntax
This also happens for:
SIM_STR_CAPACITY = 640_000
SIM_ARGV_CAPACITY = 640_000

Note: Because I'm using Windows, I am using a Ubuntu emulator found in the Windows Store

[rexim]

@TNTMaster58 what version of python do you use?

I currently use python version 3.9.7

[kolumb]

BTW, I installed Debian from Windows Store, it has python version 3.7.3, works fine: