Pretty sure Muon software is dead and buried. There hasn't been a plugin update for years, not to mention the time since the last new plugin. Shame, as I think tau2 was always better sounding than most 303 emulations, but it's the way it has to be, I guess... Luckily there are good alternatives to most plugins nowadays, including Muon synths.
As I have mentioned repeatedly over the years, I've been doing contract work in the audio software business for well over a decade now. I work behind the scenes and try to stay out of the spotlight.
I've also been saying for years that I would like to update the old Muon-branded products and it's true, I really would. No doubt I could make them a million times better. Unfortunately it just isn't financially viable.
The harsh reality is that while it isn't impossible to make a living from audio software, it is very, very hard. Many businesses fail, The KVR database is full of products from my contemporaries gathering dust, linking to websites long gone.
Back in the hazy, crazy early days of the VST plugin market it was possible for a one-man band like Muon to gain a lot of international attention because we were first. We were not the best, we were just first. So I made a few plugins, got a bit of money, and wondered what the heck to do next. Sales were dramatically lower than I originally anticipated, the competition started to quickly make better products, and Muon nearly went bust. Piracy was a massive factor in this too, though not the only one.
I had big plans but after years of making heavy financial losses I was ready to call time on the whole thing and close up shop. Thankfully I was able to make some money contracting and I've done it ever since.
I help my clients ramp up to meet the challenges of this difficult and frustrating market. I help them design better products, reduce their development times, reduce their support burden, and thus be more profitable - which in this business is essential to growth.