How to determine the availability of an API?

I want to use the Gitlab API in an application which should be able to connect to any Gitlab version (Enterprise & Community) or at least to a minimum version.
The documentation does not tell in which version of Gitlab an API was introduced or I did not see it.

Is there a place where I can see in which version of Gitlab an API was introduced?
I would like to be able to tell customers what is the minimum version of Gitlab we support.

For example: I want to use the Update file API [1] but I noticed that the last_commit_id parameter was was introduced only recently [2].

Edit: Is there any way to get the documentation from an earlier version of Gitlab?

[1] https://docs.gitlab.com/ee/api/repository_files.html#update-existing-file-in-repository
[2] https://gitlab.com/gitlab-org/gitlab-ce/issues/32642

To answer my own question (Though I would like a better solution).

I started a docker image of the earliest Gitlab I could find and went to /help/api/README.md.
This way I can see the documentation for an earlier (minimum) version.

Edit: One can see the documentation from the old version on github.
Example: https://github.com/gitlabhq/gitlabhq/tree/v7.8.3/doc/api