After a month into continuous development, the progress looked decent. Decent enough for us to share a launch date and a countdown (~90 days) on the landing page.
Launch date which we didn't meet because of the hidden complexity that was not yet uncovered, and because of unexpected life events. Once we realised we wouldn't make it, we postponed it by 2 months and informed the waiting list. And that 2nd date we didn't meet either, because of the same reasons as before.
That time we didn't risk with another date and just informed the waiting list that we'd let them know when the early access was available.