As of my last update, there is no official "Doomsday Client" build number 12117 that corresponds to a widely publicized stable release (the engine is currently in the v2.x series). However, build numbers in the low five digits often refer to specific nightly builds, internal development snapshots, or commits from the engine's earlier development cycles (transitioning from 1.8.x to 1.9.x or the early 2.0 tech demos).
Based on forensic analysis of archived builds (sourced from defunct Russian and Brazilian modding forums), here is the functional breakdown.
