Download the old versions of ASCOM from here.
I put these here as I was searching for old ASCOM versions to see if it was ASCOM that was making problems for my FocusMax software, it wasn’t in the end.
These old versions are not supported by the ASCOM team anymore, so you are on your own.
I would always recommend using the latest ASCOM version, which is available from the ASCOM website.
|ASCOM v5.5.1 Update||Download|