I decided to Google for the StackExchange API. The first link on Google is:
This itself transforms into:
This has a big notice at the top saying "The V1.x family of APIs is obsolete, having been replaced by the V2.x family", which in turn links to:
...which finally links to:
Can http://api.stackoverflow.com instead redirect directly to the V2.0 API?
A link can then be added to the V2.0 API site to point back to the V1.x documentation for anyone still needing to access that.