Not sure if I am replying correctly.
The EVP KDF APIs have never been in a release. There is no example of their use that works on anything except master and the existing example didn't work. The use of ctrl functions was removed because of the upcoming changes and a general drift to OSSL_PARAMs instead.
Earlier releases of OpenSSL required either calling the KDF functions directly or using the PKEY interface kludge.
- No, you're not replying correctly. You should reply on the thread and not start a new one on a different page.
- Removing the exiting information was the wrong choice. Add a new example with the new information.