It was previously that a 5 was the only pass and a 4 would be acceptable only for 6th form maths and English resit purposes, and for the first two years only.
5 weeks before the kids started sitting the actual GCSEs, the government bottled it. They realised that it would be a disaster in the summer when the pass rate for English and maths plummeted by 23% as it is set to do for the 5. Gove said years ago that this would happen and people would just have to live with it.
They botched it and said now a 4 was a pass too, a 'standard pass'. That this would count for resit requirements, university entry, jobs, forever. Now in August the pass rate will be the same as last year, saving the government embarrassment.
They announced this in the evening of the day before the Article 50 notification in order to bury the news, even though they knew weeks before they were going to do it.
We will still have a results shambles, but that has been postponed to January. School pass rates will be set by the 5 grade not the 4, so we will see the 23% pass rate reduction then. Crucially this will only affect schools and not pupils so voters will care less.
The message has yet to get out to employers, universities and so on because the whole thing has been a shitshow from start to finish.