On Steam you should have the newest 3.8 Version. So all is fine, nothing todo. 😉
GOG-Version
Sadly the GOG Version is still on 3.7.2.1, but you can update it manually with the CD-Patch!
Download und run the 3.8 CD-Update, ignore all the warnings and just install it: https://worms2d.info/files/WA_update-3.8_%5BCD%5D_Installer.exe
After that, go into your Worms Armageddon Install directory and replace your WA.EXE with this one: WA.EXE
And that’s it! The game should run fine now with 3.8.
I’ve done the work for you and changed the byte at hex offset 296712 to 02, which turns it to the GOG-Version. You can read more about it here: https://www.reddit.com/r/worms/comments/hz7hzg/a_solution_to_worms_armageddon_v38_on_gog_still/
Retail Versions:
Just download and install the 3.8 Update and you’re good to go:
https://worms2d.info/files/WA_update-3.8_%5BCD%5D_Installer.exe
Check latest Version here: https://worms2d.info/Updates_(Worms_Armageddon)