Here is the list of 77W leaving in 2020 in the following:

A6-EBB - Due to leave in March 2020
A6-EBC - Due to leave in April 2020
A6-EBE - Due to leave in August 2020
A6-EBG - Due to leave in November 2020
A6-EBI - Due to leave in December 2020
A6-EBJ - Due to leave in end of December 2020

2021 TBA:
A6-EBQ - EBW leaving in end of FY2020 and 2021 will ALSO see A6-ECx and EGx began retirement as well. Planes that are build prior to A6-EGP will be retired. No confirmation yet regarding the 2021 fleet plan but all I know is the last remaining A6-EBx (Except A6-EBY) is retiring in 2021.