.ruby-version
2.3.3
# ruby version 2.3.3 from raspbian stretch
# to compile it on a more recent linux see: https://github.com/rbenv/ruby-build/wiki#openssl-usrincludeopensslasn1_mach102-error-error-this-file-is-obsolete-please-update-your-software
# on openSUSE:
# sudo zypper rm libopenssl-1_1-devel
# sudo zypper in libopenssl-1_0_0-devel