Is there a reason that documentation version of the language and official version don't match?

[xwu (Xiaodi Wu)]

Where is the documentation for the most current "Release" version of Swift 4.1X? All I see is the 4.2 BETA

Can someone tell me how to get to the Language and Reference Guides for the current RELEASED 4.1 version of Swift? All I can see is BETA 4.2 documentation and can't find a link to the current release docs. Thanks in advance.