Valve has introduced achievement sets in the Steam client beta, allowing developers to group achievements for a game's base campaign, DLC, seasons or other content separately.

Each set tracks its own completion progress. In games that adopt the feature, additional DLC or seasonal achievements can sit outside the base-game set, so players can retain that set's 100% completion without earning every later addition.

The redesigned achievements page brings progress information together and allows direct comparisons with up to three friends at once. Support depends on developers organising their games' achievements into sets; the change does not automatically separate every game's existing list.

The feature is currently available through the Steam client beta.

Sources: Valve announcements, PC Gamer.