KeyError: 'Definition'

[GingerAvalanche]

          Hello, I'm having a problem as well, can't install any mod. Mine says 

Traceback (most recent call last):
File "c:\users\ushir\appdata\local\programs\python\python38\lib\site-packages\bcml\install.py", line 295, in install_mod
tmp_dir = open_mod(mod)
File "c:\users\ushir\appdata\local\programs\python\python38\lib\site-packages\bcml\install.py", line 122, in open_mod
upgrade.convert_old_mod(rulesdir, delete_old=True)
File "c:\users\ushir\appdata\local\programs\python\python38\lib\site-packages\bcml\upgrade.py", line 38, in convert_old_mod
info = parse_rules(mod / "rules.txt")
File "c:\users\ushir\appdata\local\programs\python\python38\lib\site-packages\bcml\upgrade.py", line 74, in parse_rules
"name": str(rules["Definition"]["name"]).strip(""' "),
File "c:\users\ushir\appdata\local\programs\python\python38\lib\configparser.py", line 960, in getitem
raise KeyError(key)
KeyError: 'Definition'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "c:\users\ushir\appdata\local\programs\python\python38\lib\site-packages\bcml_api.py", line 33, in status_run
data = func(*args, **kwargs)
File "c:\users\ushir\appdata\local\programs\python\python38\lib\site-packages\bcml\install.py", line 264, in do_and_refresh
res = func(*args, **kwargs)
File "c:\users\ushir\appdata\local\programs\python\python38\lib\site-packages\bcml_api.py", line 380, in install_mod
mods = [
File "c:\users\ushir\appdata\local\programs\python\python38\lib\site-packages\bcml_api.py", line 381, in
install.install_mod(
File "c:\users\ushir\appdata\local\programs\python\python38\lib\site-packages\bcml\install.py", line 312, in install_mod
raise util.InstallError(err) from err
bcml.util.InstallError: An error occured when installing your mod. 'Definition'
Your mod is being removed, and no changes have been made.

Originally posted by @Ayaya70 in #436 (comment)

[GingerAvalanche]

This is due to the removal of the bnp upgrader in v3.10.5, which was done because the upgrader used code that didn't work on python 3.9 or above. It only affects very old bnp's. We didn't even realize that so many of those old bnp's were still in use.

We will not be adding the upgrader back in, for many reasons, but the most important is that we will not be making any more changes to bcml. Going forward, it's suggested that you use ukmm instead.

But if you absolutely must use old bnp's with bcml, make sure you are using python 3.7 or 3.8, and install the last bcml version that had the upgrader, with the console command pip install bcml==3.10.4