Techies got an old ability back and was reworked in patch 7.41

Valve heavily updated Techies in patch 7.41 for Dota 2, partially bringing back old mechanics and noticeably changing the hero gameplay.

The main addition is the new innate ability M.A.D., which increases mana regen based on the hero’s maximum mana. Also, after death Techies leave behind a barrel, that explodes after a short delay, dealing damage based on max mana in an area. The ability also got an upgrade with Aghanims Shard: now it can be used actively, placing an invisible barrel that can be detonated later.

Credits: Valve Corporation

It is notable that the ability uses the icon of the old green barrel, which Valve previously replaced. Changes also affected other skills. Reactive Tazer can now always be cast on allies, and its cast range was increased, while it no longer has an upgrade with Aghanims Shard. Blast Off! was reworked: self damage is now applied before dealing damage to enemies, and during the jump Techies are no longer stunned, but instead get disarmed and rooted.

Proximity Mines were also updated — now the damage source is considered to be the hero, not the mines. Minefield Sign is now only available with Aghanims Scepter.

Additionally, the developers changed talents: at level 15 the mana regen bonus was replaced with a Reactive Tazer buff, and at level 25 the damage bonus was slightly increased,