Based on the specific build tag v20181009 , this refers to the final official version of before the massive legacy update (which introduced the untested "Launcher"). This version is highly sought after for its stability and for running certain mods that broke after later updates.
The Alien Rulers (Berserker Queen, Viper King, Archon King) are brutally strong. According to XCOM 2 Fandom Wiki, you should make sure your squad is well-equipped before encountering them.
Adding a brand-new soldier class—the SPARK mechanized combat unit—and a unique narrative mission. The Significance of the v20181009 Update
