The new 77X Business Class is ready to go and no 77X will fly before 2025.
SQ has not materially improved their J product in many years and the 2017/2018 J on the A380 has not many fans: it's the firmest seat on the planet and sleeping is kind of difficult.
I have seen the new 77X J product and I think it would help SQ's image as a leading carrier in premium classes.
SQ has ruled out First Class since the start of ULH flights. Nothing has changed here.