diff --git a/TESTING.md b/TESTING.md
index 18a315d..4d6f583 100644
--- a/TESTING.md
+++ b/TESTING.md
@@ -84,7 +84,7 @@ The Makefile accept the following options
     - "mariadb:10.4.24"
     - "mariadb:10.5.18"
     - "mariadb:10.6.11"
-  - Description: The name of the container to use for the service containers that will host a primary database and two replicas. Either MYSQL or MariaDB. Use ':' as a separator. Do not use short version, like mysql:8 for instance. Our tests expect a full version to filter tests precisely. For instance: `when: db_version is version ('8.0.22', '>')`.
+  - Description: The name of the container to use for the service containers that will host a primary database and two replicas. Either MYSQL or MariaDB. Use ':' as a separator. Do not use short version, like `mysql:8` (don't do that) because our tests expect a full version to filter tests precisely. For instance: `when: db_version is version ('8.0.22', '>')`. You can use any tag available on [hub.docker.com/_/mysql](https://hub.docker.com/_/mysql) and [hub.docker.com/_/mariadb](https://hub.docker.com/_/mariadb) but GitHub Action will only use the versions listed above.
 
 - `connector`
   - Mandatory: true