I am currently working on removing the API documentation version list from api.mongodb.com. This involves removing the https://api.mongodb.com/ruby/ page and any links to it.
I noticed that each of the links in the Ruby driver documentation link to http://api.mongodb.com/ruby/current/ regardless of the version of the reference documentation. 
We should:

• remove links to api.mongodb.com/ruby on any API documentation
• fix the reference documentation to link to the API version that matches the selected reference documentation version