Complex sentence: In 2012, the group announced that Richardson had rejoined them permanently, and in the following year they celebrated their 20th anniversary and released their first independent album, "In a World Like This" (2013).
Split into simpler sentences: In 2012, the group announced that Richardson had rejoined them permanently. In the following year they celebrated their 20th anniversary and released their first independent album, "In a World Like This" (2013).