I'm glad there is Sinatra because it inspired Scalatra, which seems way more lightweight than Play :-). Keep up being lightweight!
I don't blame the authors for discontinuing old branches (1.2.x), but it makes me hesitant using Sinatra for a production website that's meant to be there for >= 2 years (though is an eon in IT).
The upgrade process is pretty smooth, the latest Sinatra release still runs all the first example apps published in 2007.
Also, the Sinatra code base is pretty small, so just because it's no longer officially maintained doesn't mean you can't run Sinatra 1.2.0. All security issues we have seen so far have all been in Sinatra dependencies (namely Rack) and never in Sinatra itself.
If you are stuck on an unmaintained Ruby version that's a way bigger issue than being stuck on an unmaintained Sinatra version. You should not run Ruby 1.8.6 in production for security reasons.
Many projects out there follow the two maintained feature versions approach, like Rails. How many versions of Sinatra should see regular releases? What about 1.1.x? Or 0.9.x?
It has also been announced with the 1.3.0 release that 1.2.x will be continued until the 1.4.0 release.
Being stuck on 1.2.x is pretty bad, as it still ships without rack-protection.
Similarly, I'm a fan of Mojolicious, and Mojolicious::Lite looks to have been heavily inspired by Sinatra. I'm not sure exactly how far that inspiration goes though, as I see Sinatra explained as best used when you want something light, and Mojolicious looks to scale quite well to larger apps.
That is a typical explanation but there is nothing stopping you from using Sinatra for building large apps. In fact I find myself just as productive with Sinatra as I was with Rails for building very feature full apps.
lightweight as in activerecord and all the other things aren't bundled in by default. you bundle what you need. sinatra doesnt assume that you need an orm or template language. think of sinatra as a domain specific language for creating websites, but you could tack on orm or templates as you see fit.
I don't blame the authors for discontinuing old branches (1.2.x), but it makes me hesitant using Sinatra for a production website that's meant to be there for >= 2 years (though is an eon in IT).