diff --git a/changelogs/unreleased/28524-gitlab-ci-yml-coverage-key-is-unknown.yml b/changelogs/unreleased/28524-gitlab-ci-yml-coverage-key-is-unknown.yml
new file mode 100644
index 0000000000000000000000000000000000000000..eda5764c13ead8bb305bf2576ba7ef1ee36bcdc2
--- /dev/null
+++ b/changelogs/unreleased/28524-gitlab-ci-yml-coverage-key-is-unknown.yml
@@ -0,0 +1,4 @@
+---
+title: Document when current coverage configuration option was introduced
+merge_request: 9443
+author:
diff --git a/doc/ci/yaml/README.md b/doc/ci/yaml/README.md
index a73598df81244b4484eafa8063d22d8f63a041b2..dd3ba1283f8cad0567bf82157813f8cbd747df95 100644
--- a/doc/ci/yaml/README.md
+++ b/doc/ci/yaml/README.md
@@ -1003,6 +1003,9 @@ job:
 
 ### coverage
 
+**Notes:**
+- [Introduced][ce-7447] in GitLab 8.17.
+
 `coverage` allows you to configure how code coverage will be extracted from the
 job output.
 
@@ -1361,3 +1364,4 @@ CI with various languages.
 [ce-6669]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6669
 [variables]: ../variables/README.md
 [ce-7983]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7983
+[ce-7447]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7447