According to the announcement (view here), Appeon and SAP will offer different product lines of PowerBuilder.

The Appeon's product line will integrate with the bugs fixed in the SAP's product line. In the case of the GA version of Appeon PowerBuilder 2017 R2, the bug fixes in SAP PowerBuilder 12.6 EBF 4166 (which is released in 2017 Q3) have been integrated.