There was a tentative December 2023 target which wasn’t met. That’s how things are sometimes. Also, people are not “owed” news, or an explanation. But whether or not the intention is to keep this project going, why not just say so?
It can’t feel great to have this hanging over your head, and if it’s being worked on the dreadful guilt-unmotivation-delay negative feedback loop can’t possibly be worth eventually coming back with an all-at-once “Sorry I’m late and didn’t keep you posted, but here’s the update!”.
Really, I imagine just biting the bullet and writing a couple sentences somewhere would go a very long way for everyone involved.