Key changes included:
Have you experienced the iw_22.iwd patch? Do you remember which mod you lost access to? Share your memories in the comments below (or on the MW2 Legacy Modding Discord).
For years, Activision turned a blind eye. VAC (Valve Anti-Cheat) banned specific hash-checks, but modders simply repacked the same data with a different compression timestamp.
If you have a non-Steam backup of MW2 from before 2023 (e.g., a retail DVD copy or an old cracked version), those versions do not have the Steam-enhanced validation. You can use any iw_22.iwd mod freely. This is often used by LAN party organizers.