The Source engine has since been used and updated over the years, with DotA 2 being one the games that utilized it. However that has all changed because according to a tweet from the official DotA 2 account (via Engadget), the Reborn update that upgrades the game to the Source 2 engine has begun rolling out.
Last week we reported that Valve was planning to roll out the update soon, and with the roll out taking place today, DotA 2 is now officially the first Valve game to use the Source 2 engine. This represents a huge change in the way the game looks. There is also updates to the game’s user interface, so it might take some getting used to if you weren’t part of its beta.
In the meantime as for Valve’s other games, the company did state that maybe Counter-Strike: Global Offensive will be updated to Source 2 one day. There was no mention of the company’s other games like Team Fortress 2 getting the Source 2 update, but we wouldn’t surprised if it wasn’t at the very least considered.