diff --git a/scripts/upgrade b/scripts/upgrade
index 5bdf034..28abba2 100755
--- a/scripts/upgrade
+++ b/scripts/upgrade
@@ -137,6 +137,18 @@ then
     ynh_use_logrotate --logfile /var/log/matrix-$app --nonappend
 fi
 
+#=================================================
+# MIGRATION 3 : USE STANDARD ACCESS FOR CERTIFCATE
+#=================================================
+
+# Fix issue about certificates access
+if [ ! $(grep "ssl-cert:x:[0-9]*:.*$app" /etc/group) ]
+then
+    ynh_script_progression --message="Use standard access for certificate..." --weight=1
+
+    adduser turnserver ssl-cert
+fi
+
 #=================================================
 # SPECIFIC UPGRADE
 #=================================================