diff --git a/lib/dml/mssql_native_moodle_database.php b/lib/dml/mssql_native_moodle_database.php
index 47c41779064..212f44fccf2 100644
--- a/lib/dml/mssql_native_moodle_database.php
+++ b/lib/dml/mssql_native_moodle_database.php
@@ -287,6 +287,13 @@ class mssql_native_moodle_database extends moodle_database {
         return $info;
     }
 
+    /**
+     * Returns if the RDBMS server fulfills the required version
+     *
+     * @param string $version version to check against
+     * @return bool returns if the version is fulfilled (true) or no (false)
+     * @todo Delete this unused and protected method. MDL-32392
+     */
     protected function is_min_version($version) {
         $server = $this->get_server_info();
         $server = $server['version'];
diff --git a/lib/dml/oci_native_moodle_database.php b/lib/dml/oci_native_moodle_database.php
index 71a38eeaf1c..046e377550d 100644
--- a/lib/dml/oci_native_moodle_database.php
+++ b/lib/dml/oci_native_moodle_database.php
@@ -296,6 +296,13 @@ class oci_native_moodle_database extends moodle_database {
         return $info;
     }
 
+    /**
+     * Returns if the RDBMS server fulfills the required version
+     *
+     * @param string $version version to check against
+     * @return bool returns if the version is fulfilled (true) or no (false)
+     * @todo Delete this unused and protected method. MDL-32392
+     */
     protected function is_min_version($version) {
         $server = $this->get_server_info();
         $server = $server['version'];
diff --git a/lib/dml/pgsql_native_moodle_database.php b/lib/dml/pgsql_native_moodle_database.php
index fa1b7fc8892..96863b7ee07 100644
--- a/lib/dml/pgsql_native_moodle_database.php
+++ b/lib/dml/pgsql_native_moodle_database.php
@@ -251,6 +251,13 @@ class pgsql_native_moodle_database extends moodle_database {
         return array('description'=>$info['server'], 'version'=>$info['server']);
     }
 
+    /**
+     * Returns if the RDBMS server fulfills the required version
+     *
+     * @param string $version version to check against
+     * @return bool returns if the version is fulfilled (true) or no (false)
+     * @todo Make this method private. MDL-32392
+     */
     protected function is_min_version($version) {
         $server = $this->get_server_info();
         $server = $server['version'];
diff --git a/lib/dml/sqlsrv_native_moodle_database.php b/lib/dml/sqlsrv_native_moodle_database.php
index 01f9241a94e..31f778f823f 100644
--- a/lib/dml/sqlsrv_native_moodle_database.php
+++ b/lib/dml/sqlsrv_native_moodle_database.php
@@ -277,10 +277,11 @@ class sqlsrv_native_moodle_database extends moodle_database {
     }
 
     /**
-     * Get the minimum SQL allowed
+     * Returns if the RDBMS server fulfills the required version
      *
-     * @param mixed $version
-     * @return mixed
+     * @param string $version version to check against
+     * @return bool returns if the version is fulfilled (true) or no (false)
+     * @todo Delete this unused and protected method. MDL-32392
      */
     protected function is_min_version($version) {
         $server = $this->get_server_info();