GeneXus X Evolution 3 Upgrade 13 previews were part of the releasing process of Upgrade 13. They were intended to round up Upgrade 13 and facilitate adoption once released.
Upgrade 13 has been released on April 2nd, 2017
GeneXus: http://www.genexus.com/developers/RN?,0,,0;4;xev3;12;13;;
GXserver: http://www.genexus.com/developers/RN?,0,,0;6;xev3;12;13;;
GXflow: http://www.genexus.com/developers/RN?,0,,0;3;xev3;12;13;;