MathieuM you are right. It's also not fair.
As core team we are aiming towards planned release cycles this year, for beta 9 we failed terribly. Here's the background on that.
First of all, most of the high level decisions are made by Toby and Franz, they are architects of Flarum and most often require each others' opinion on whether their own ideas are the right ones for this project (peer review, second opinion) to reach the best quality possible.
Toby has been less active this year up until now, Franz and I are primarily back end developers, meaning that any change (like the IE bug) requires a much larger time investment from either of us to get it done.
With the increase in attention Flarum has been receiving "just" doing the development aspect of running an open source project no longer is sufficient. It's time we look at our future, our organisation and protecting our intellectual property. This is something I have been shifting my focus to lately, as a consequence less commits were made by me. In terms of stable development we haven't been living up to expectations, something I've heard time and time again. Part of my focus to the organisational side is to improve that.
Don't. We're actually glad to have such a committed community backing our efforts. Without your continued interest in the project we'd never be where we are now. But the current formation of our team is still pretty new to all of this, most actually know more about development than organisational matters. Our hopes are still on Flarum, some of our core team might eventually even be working on this project full time at some point.
Right now, we need to focus on getting better on multiple levels, if you feel like you are able to contribute to the project, reach out to one of the staff members on discord.