GeneXus 15 Upgrade 6 previews were part of the releasing process of Upgrade 6. They were intended to round up Upgrade 6 and facilitate adoption once released.
Upgrade 6, build 116888, has been released on August 29th, 2017.
at GeneXus 15 Upgrade 6.
GeneXus: http://www.genexus.com/developers/RN?,0,,0;4;V15;5;6;;
GXserver: http://www.genexus.com/developers/RN?,0,,0;6;V15;5;6;;
GXflow: http://www.genexus.com/developers/RN?,0,,0;3;V15;5;6;;