I have a working program to validate a Yubikey OTP based on the specification at https://developers.yubico.com/yubikey-val/Validation_Protocol_V2.0.html

But https://developers.yubico.com/yubikey-val/ indicates that project is End of Life.

Where can I find current API documentation to validate a OTP?

I think that Yubicloud (https://www.yubico.com/products/yubicloud/) is supposed to supersede the previous project. It seems that https://developers.yubico.com/yubico-java-client/ might be a current java library. I guess I could reverse engineer that, but would really like to have the raw API doc.