The latest Release corresponding to this channel is GeneXus 18 Upgrade 3
Previous upgrades (of GeneXus 18) can be found here.
http://www.genexus.com/genexus18
http://www.genexus.com/v18
http://www.genexus.com/v18-download
To GeneXus 17, the last release was GeneXus 17 Upgrade 11, and previous ones can be found here.
To GeneXus 16, the last release was GeneXus 16 Upgrade 11, and previous ones can be found here.
To GeneXus 15, the last release was GeneXus 15 upgrade 12, and previous ones can be found here.
Entry points to even older versions than these ones can be found at GeneXus Versions.
GeneXus Preview Channel