I used to use the preview version of QnA Maker and with it the v3.0 API had this train endpoint which could be used to reinforce a correct answer:
Now I'm migrating to QnA Maker GA and it uses the v4.0 API. I cannot find the train endpoint anywhere in the documentation of the v4.0 APi. Does the train endpoint still exist in the v4.0 API?
Official reply has been made on Github issue by Prashant Choudhari from Microsoft:
We do not have the train API in V4. We are re-thinking this feature and will re-enable an advanced version in a future release.
See here: https://github.com/Microsoft/BotBuilder-CognitiveServices/issues/106
来源：https://stackoverflow.com/questions/50401507/training-qna-maker-with-api-v4-0