I was going to say that OTP was certainly done, but it got a patch last month [1]. I don't expect many more? But just because OTP 22 is done, doesn't mean OTP is done. There's obviously lots of optimization available that can be done, as well as ports to future architectures, and the requirements aren't set in stone; it's got a TLS stack, so that's never done for example.
[1] https://www.erlang.org/patches/otp-22.3.4.27