A nice move by Valve to improve the modding scene - as mods on the Steam Workshop can now support multiple game versions.

There's a little work required by both game developers and modders to get it all to work together, but the system sounds quite nice. Might mean in future, eventually anyway, we'll see less compatibility issues when developers put out big updates to their games. Valve put up two separate blog posts on it across Steamworks and Steam Workshop to cover all the details, and they have a new documentation page to cover it.