diff --git a/admin_manual/installation/source_installation.rst b/admin_manual/installation/source_installation.rst
index 13d0796b8..caefdecb2 100644
--- a/admin_manual/installation/source_installation.rst
+++ b/admin_manual/installation/source_installation.rst
@@ -105,7 +105,7 @@ Required:
 * PHP module curl
 * PHP module dom
 * PHP module GD
-* PHP module hash
+* PHP module hash (only on FreeBSD)
 * PHP module iconv
 * PHP module JSON
 * PHP module libxml (Linux package libxml2 must be >=2.7.0)