This document lays out the feature and API set for the 3.1.0 release of the M2T Acceleo project. The Acceleo component is an open source component under the Eclipse Modeling / Model-To-Text (M2T) project. Its primary goal is to provide an implementation of the MOF Model-To-Text OMG standard. The Indigo release of Acceleo introduces no API or feature breakage, and is thus labeled 3.1.0.