gem update caused error: undefined method ssl_version - ruby-on-rails

Question

I try to update gem in my macOS but the following error occurs:
$ RUBYOPT= gem update --system
ERROR: While executing gem ... (NoMethodError)
undefined method `ssl_version=' for #<OpenSSL::SSL::SSLContext:0x007f8561047638>
Did you mean? ssl_timeout=
The output of gem update and gem install {package_name} are the same.
The output of gem env version or gem --version is:
3.0.3
The output of openssl version is:
LibreSSL 2.6.5
How can I resolve the issue?
macOS version: 10.14.4
Output of gem env:
RubyGems Environment:
- RUBYGEMS VERSION: 3.0.3
- RUBY VERSION: 2.4.0 (2016-12-24 patchlevel 0) [x86_64-darwin16]
- INSTALLATION DIRECTORY: /Users/adv/.rvm/gems/ruby-2.4.0
- USER INSTALLATION DIRECTORY: /Users/adv/.gem/ruby/2.4.0
- RUBY EXECUTABLE: /Users/adv/.rvm/rubies/ruby-2.4.0/bin/ruby
- GIT EXECUTABLE: /usr/local/bin/git
- EXECUTABLE DIRECTORY: /Users/adv/.rvm/gems/ruby-2.4.0/bin
- SPEC CACHE DIRECTORY: /Users/adv/.gem/specs
- SYSTEM CONFIGURATION DIRECTORY: /Users/adv/.rvm/rubies/ruby-2.4.0/etc
- RUBYGEMS PLATFORMS:
- ruby
- x86_64-darwin-16
- GEM PATHS:
- /Users/adv/.rvm/gems/ruby-2.4.0
- /Users/adv/.rvm/rubies/ruby-2.4.0/lib/ruby/gems/2.4.0
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :backtrace => false
- :bulk_threshold => 1000
- REMOTE SOURCES:
- https://rubygems.org/
- SHELL PATH:
- /Users/adv/.rvm/gems/ruby-2.4.0/bin
- /Users/adv/.rvm/gems/ruby-2.4.0#global/bin
- /Users/adv/.rvm/rubies/ruby-2.4.0/bin
- /Users/adv/.fastlane/bin
- /Library/Frameworks/Python.framework/Versions/3.7/bin
- /usr/local/sbin
- /Users/adv/.rbenv/shims
- /Users/adv/.rvm/bin
- /Users/adv/.fastlane/bin
- /Library/Frameworks/Python.framework/Versions/3.7/bin
- /usr/local/sbin
- /Users/adv/.rbenv/shims
- /usr/local/bin
- /usr/bin
- /bin
- /usr/sbin
- /sbin
- /usr/local/share/dotnet
- /Library/Frameworks/Mono.framework/Versions/Current/Commands
- /Users/adv/android-sdks/platform-tools
- /Users/adv/android-sdks/tools
- /opt/metasploit-framework/bin
- /opt/metasploit-framework/bin
- /Users/adv/android-sdks/platform-tools/
- /Users/adv/android-sdks/tools/
- /opt/metasploit-framework/bin
- /opt/metasploit-framework/bin
Output of which gem:
/Users/adv/.rvm/rubies/ruby-2.4.0/bin/gem
Output of rbenv versions:
system
* 2.4.1 (set by /Users/adv/.rbenv/version)
Output of ruby -ropenssl -e "puts OpenSSL::OPENSSL_LIBRARY_VERSION":
OpenSSL 1.1.1b 26 Feb 2019
Output of rvm list:
=* ruby-2.4.0 [ x86_64 ]
# => - current
# =* - current && default
# * - default
UPDATE: After I removed rvm and rbenv completely (and restarted the Terminal session), I try to execute gem update again, here is the result:
$ gem update
Updating installed gems
Updating CFPropertyList
Fetching: CFPropertyList-3.0.0.gem (100%)
ERROR: While executing gem ... (Gem::FilePermissionError)
You don't have write permissions for the /Library/Ruby/Gems/2.3.0 directory.
I think it now uses macOS's system ruby again.
Here are some outputs:
Output of gem -v:
2.5.2.3
Output of ruby -v:
ruby 2.3.7p456 (2018-03-28 revision 63024) [universal.x86_64-darwin18]
Output of which gem:
/usr/bin/gem
Ouput of which ruby:
/usr/bin/ruby
My aim is to use gem without problems (install & update, etc). What should I do next?

Answer 1

OpenSSL::SSL::SSLContext#ssl_version= appeared in ruby 1.8.7, mac os has 2.3.7 built-in
Just checked on 10.14.2 -
require 'openssl'; OpenSSL::SSL::SSLContext.new.ssl_version="TLSv1"
works fine even on system ruby, OpenSSL versions are the same as yours.
The only thing left to suspect is rbenv conflict with rvm, because you have both installed, it may mess loaded libraries and ruby compilation. I suggest removing one of them completely (also not forget to start new shell session after this) and reinstall broken ruby.