-Fixed a serious bug that would cause the game to crash on group creation
-Changed Lord of Avernus's model to the one introduced in 6.59
-Gave Bat Rider an air-to-air attack while flying, which should remove the bug where he would permanently gain damage upon flying down
-Removed warning message for incomplete AIs when playing Deathmatch (or new Formless Mode)
-Formless can now learn Quill Spray, Bristleback, Warpath
-Fixed a bug with Formless not being able to reset Clockwerk's abilities
-Added new single-player mode: Formless mode (-formless, -fm), which will allow the player to play as Formless and cause the AI to cycle through heroes as they die. No limitations on duplicate heroes picked by AI (except Meepo, who has been disabled). Abilities are not lost when Formless dies, this may change in future versions. -fm can be combined with non-gamemode switches (like -fr, -st, -ne, etc.).
Source : here