The 20 episodes will be selected from the vast Generations library, and will be based on "selected milestones that saw a change in the soap," SABC1 tells me.
Sister channel SABC3 is showing both the regular episode in its regular timeslot as well as the very first episode of Isidingo today to celebrate Isidingo's 15th anniversary of the soap.
It's not yet clear whether SABC1 and Generations will be doing the same in September by keeping the regular Generations episode in its regular timeslot and then substituting the special 20th anniversay Generations episodes in an additional timeslot.
This is important - and a possibility - because SABC1 and SABC3 is still trying to move the American soap The Bold and the Beautiful from SABC1 to SABC3. SABC1 constantly struggles to find replacement content for The Bold and the Beautiful's timeslot in time, which then causes SABC3 - which is ready to take over Bold, to postpone the plan.
After two previous failed tries and attempts which saw the Bold move and plan put on hold - the last try would have been in June this year - both SABC1 and SABC3 are trying to move The Bold and the Beautiful to SABC3 during September.
If the move does happen this time, it could be that the Generations 20th anniversary episodes are placed in Bold's spot on SABC1, with the regular Generations episode remaining.
However, its also forseeable that Bold moves anyway in September, that SABC1 finds other content for Bold's empty spot, and that the special Generations episodes are shown in the regular Generations spots which means no new Generations episodes for 20 days.