diff --git a/src/script.php b/src/script.php
index d78ceb6..c48027e 100644
--- a/src/script.php
+++ b/src/script.php
@@ -93,6 +93,7 @@ class Tpl_MokoonyxInstallerScript implements InstallerScriptInterface
             $this->replaceCassiopeiaReferences();
             $this->clearFaviconStamp();
             $this->cleanMediaFolder();
+            $this->removeDeletedFiles();
             $this->lockExtension();
         }
 
@@ -483,6 +484,68 @@ class Tpl_MokoonyxInstallerScript implements InstallerScriptInterface
         }
     }
 
+    /**
+     * Remove files and directories that were shipped in previous versions
+     * but have since been deleted from the package.
+     *
+     * Joomla's installer never deletes files on upgrade — it only
+     * adds/overwrites.  This method fills that gap so stale overrides
+     * and deprecated assets don't linger on disk.
+     *
+     * Maintain this list: when you delete a file from the repo, add its
+     * path here (relative to the template root) so existing installs
+     * get cleaned up on the next update.
+     */
+    private function removeDeletedFiles(): void
+    {
+        $templateRoot = JPATH_ROOT . '/templates/' . self::NEW_NAME;
+
+        // Paths relative to templates/mokoonyx/
+        $deletedFiles = [
+            // JoomGallery template overrides — removed in 02.19.00
+            'html/com_joomgallery/category/default.php',
+            'html/com_joomgallery/category/default_cat.php',
+            'html/com_joomgallery/category/index.html',
+            'html/com_joomgallery/gallery/default.php',
+            'html/com_joomgallery/gallery/index.html',
+            'html/com_joomgallery/image/default.php',
+            'html/com_joomgallery/image/index.html',
+        ];
+
+        // Directories to remove (only if empty after file deletion)
+        $deletedDirs = [
+            'html/com_joomgallery/image',
+            'html/com_joomgallery/gallery',
+            'html/com_joomgallery/category',
+            'html/com_joomgallery',
+        ];
+
+        $removed = 0;
+
+        foreach ($deletedFiles as $relPath) {
+            $file = $templateRoot . '/' . $relPath;
+            if (is_file($file)) {
+                @unlink($file);
+                $removed++;
+            }
+        }
+
+        foreach ($deletedDirs as $relPath) {
+            $dir = $templateRoot . '/' . $relPath;
+            if (is_dir($dir)) {
+                // Only remove if empty
+                $entries = @scandir($dir);
+                if ($entries && count($entries) <= 2) { // . and .. only
+                    @rmdir($dir);
+                }
+            }
+        }
+
+        if ($removed > 0) {
+            $this->logMessage("Removed {$removed} deprecated file(s) from previous versions.");
+        }
+    }
+
     private function logMessage(string $message, string $priority = 'info'): void
     {
         $priorities = [