More Robust 3.x to 4.x documentation

Great work on CI4. I'm reworking an existing application from CI3.x to CI4.x and you do have a basic documentation page on the general idea but I'm finding that dozens of features from 3.x were removed with some replaced by another feature in CI4... Since that documentation isn't included I'm having to dig all over the place to try to figure out how to do it. It would be helpful if either one or both of the below were in place:

1- In the CI4 documentation there was a mention of the CI3.x counterpart when it's different. (e.g., the Request/Response class documentation would reference that in 3.x this was Input/Output)
2- A table in the CI3.x to CI4.x reference material that gave a cheatsheet of equivalents for the different versions. (e.g., input::post_get() => request::getPostGet())