Ruby 2.6.0.rc1 released yesterday! https://www.ruby-lang.org/en/news/2018/12/06/ruby-2-6-0-rc1-released/
I did scratch build of r66252 yesterday, which is pretty close to RC1 (r66253). Nevertheless there are still some things broken upstream:
https://bugs.ruby-lang.org/issues/15391
https://bugs.ruby-lang.org/issues/15335
https://bugs.ruby-lang.org/issues/15384
https://bugs.ruby-lang.org/issues/15359
Not mentioning OpenSSL
patches we carry around and they are still not in trunk :/ I am
not really happy about the upstream state of 2.6 ATM. But I
started with preparing 2.6 quite late this time, so I can blame
myself ...
Vít