diff --git a/admin/environment.xml b/admin/environment.xml
index 19997a449b3..66e4337c0de 100644
--- a/admin/environment.xml
+++ b/admin/environment.xml
@@ -957,6 +957,8 @@
           <ON_ERROR message="ziprequired" />
         </FEEDBACK>
       </PHP_EXTENSION>
+      <PHP_EXTENSION name="zlib" level="optional">
+      </PHP_EXTENSION>
       <PHP_EXTENSION name="gd" level="required">
         <FEEDBACK>
           <ON_ERROR message="gdrequired" />