Include warning about usage of dev version in compatibility checks

classes/local/setting/compatibility_check_setting.php

@@ -62,6 +62,13 @@ protected function get_html_content() {
         $recentishlocalxp = 2023100800; // Version 1.15.0.
         $humanbranch = moodle_major_version() ?: 'v?';
 
+        if ($blockxp && strpos($blockxp->release, '-dev') !== false) {
+            $messages[] = [
+                'title' => get_string('unstableversioninstalled', 'block_xp'),
+                'message' => get_string('unstableversioninstalledinfo', 'block_xp', ['version' => $blockxp->release]),
+            ];
+        }
+
         if ($localxp && $localxp->versiondb < $recentishlocalxp) {
             $messages[] = [
                 'title' => get_string('outofsyncexcessive', 'block_xp'),

lang/en/block_xp.php

@@ -576,7 +576,9 @@
 $string['tryme'] = 'Try me';
 $string['unlockfeaturewithxpplus'] = 'Unlock this feature with XP+. <a href="{$a}">Learn more</a>';
 $string['unavailable'] = 'Unavailable';
+$string['unstableversioninstalledinfo'] = 'This version of Level Up XP (block_xp) is still in development and considered unstable, please use an official release.';
 $string['upgradingplugins'] = 'Upgrading the plugins';
+$string['unstableversioninstalled'] = 'Unstable version installed';
 $string['value'] = 'Value';
 $string['visualsintro'] = 'Customise the appearance of the levels, and the meaning of the points.';
 $string['wherearexpused'] = 'Where are points used?';