Is it possible to get the comments from a tweet in version 1.1 of the Twitter API?
I know it's possible in version 2.0 but I must use version 1.1.
There is no direct ability to retrieve a thread using conversation_id in v1.1 - this functionality does not exist. You would have to try to use the search API to find replies, but this is much more difficult and less likely to find threaded responses.