A: Yes. Opt out of betas and verify files. Steam automatically reverts to the latest stable (13500921).
A: No. Source engine networking requires identical build IDs. A person on 13500921 cannot join a server running 13189342. Garrys Mod Build 13500921
For those unfamiliar with Steam’s internal versioning systems, the number "13500921" refers to a specific Manifest ID (or branch version) pushed to the Steam servers. In the context of Garry’s Mod, this build was deployed in late 2023 and early 2024 as the culmination of a massive undertaking by Facepunch Studios and Garry Newman. A: Yes
The improvements in Build 13500921 largely stem from optimized network packet handling and a more aggressive Lua garbage collector. Garrys Mod Build 13500921