Unicode Version 12.0.0 will be published in 2019, earlier than Unicode 11.0.0 in 2018. This is an issue to manage updating Ruby to Unicode 12.0.0. Details to follow.
I have confirmed that Ruby can be updated to Unicode 12.0.0 and all tests (make check) are passed correctly with the Unicode 12.0.0 beta data (http://unicode.org/versions/beta-12.0.0.html). This means that there may be only minor (or no) problems to update Ruby to Unicode 12.0.0 after it's official publication (currently planned to happen on March 5).