Description of problem
In just a few weeks (Inshallah) DNN 10 will be out, and a lot of APIs will be cleaned up.
For some developers who are not deep into DNN, this will cause some confusion, as they will stumble upon APIs which don't exist any more.
Description of solution
This would be a bit like https://v16.docs.2sxc.org/ - but I would recommend to make it better - so that you see it's an archive on every page.