Dynamic Hordes & Migration for PZ 42.20.4. Version 0.2.2 fixes the FJL DeathMixin refusal with reviewed PZOpt collision overrides and reports the actual cause of unsupported engine replacements. Persistent server-authoritative population, bounded restoration, terrain-aware migration, optional iSync/Hive adapters. Requires FJL 0.3.4+; Windows and Linux dedicated. Existing Deadflow worlds supported; unimported vanilla population saves remain unsupported.