Sorry if I missed it, but what is actually promised by Core? Is there some official statement with actual dates (obiously not referring to the powerpoint slides and twitter posts).

Based on the above points, the timeline will likely follow the below dates.
-SegWit is expected to be released in April 2016.
-The code for the hard-fork will therefore be available by July 2016.
-If there is strong community support, the hard-fork activation will likely happen around July 2017.