I was hoping for it to be something new not just an old gamemode
Why was it in development/testing for so long since it was old
Just to give a little run down and I'm going to be honest with some things xd. You're completely right, the update was in the "in progress" section on our public notion board. But that doesn't mean from day it's in development. It means that the update is in progress in our system, in discussions internally, in development, etc, and whilst things are in progress, it doesn't mean that 100% of the time our team is working on it.
Being open about Team Lucky Islands, for example, we discussed it internally. Then we added it to the public board, but we didn't act on it for weeks due to other priorities, timelines, resources, people away on holiday, everything impacts release dates. Team Lucky Islands was a pretty fast and easy thing to get out, but it wasn't a top priority, as we had other things behind the scenes we were working on.
Another example, the "EggWars Update" on the public board at the time, hasn't even started development. Due to resource allocation, priorities etc. It's in the planning stages of what we want in the update, we have an idea, then we'll assign it to a developer. I just can't give an ETA on it, sadly. I think people need to be a little relaxed with the public update board; it's not extremely strict. Treat "In progress" as "on our radar" lol.
Hope that clears some things up, any questions, lmk!