I noticed that as well. According to Mike, he’s shelving development while he works on other things. “It still works well and I am still supporting all current owners.”
So, shame it’s not being developed for now but good existing users haven’t been abandoned.
I bought 1LD’s Quick Editor Admin as a pseudo-replacement backup option and still use Sentry on a couple of sites, but there’s nothing out there that matches the blog layout of GoCMS, that isn’t a per domain price.
Rob