guides.rubygems.org/ssl-certificate-update/#instal...
https://rubygems.org/downloads/rubygems-update-2.6...C:\Users\Termux
λ gem install --local c:\warez\_dev\_src\rubygems-update-2.6.7.gem
Successfully installed rubygems-update-2.6.7
Parsing documentation for rubygems-update-2.6.7
Installing ri documentation for rubygems-update-2.6.7
Done installing documentation for rubygems-update after 93 seconds
1 gem installed
λ update_rubygems --no-ri --no-rdoc
RubyGems 2.6.7 installed
=== 2.6.7 / 2016-09-26
Bug fixes:
* Install native extensions in the correct location when using the
`--user-install` flag. Pull request #1683 by Noah Kantrowitz.
* When calling `Gem.sources`, load sources from `configuration`
if present, else use the default sources. Pull request #1699
by Luis Sagastume.
* Fail gracefully when attempting to redirect without a Location.
Pull request #1711 by Samuel Giddins.
* Update vendored Molinillo to 0.5.1. Pull request #1714 by
Samuel Giddins.
...
C:\Users\Termux
λ gem --version
2.6.7
C:\Users\Termux