diff --git a/doc/Extensions/Services.md b/doc/Extensions/Services.md
index ca2e14ed3a..ddae31f274 100644
--- a/doc/Extensions/Services.md
+++ b/doc/Extensions/Services.md
@@ -48,3 +48,4 @@ no graphs will be generated. **
 - smtp
 - pop
 - simap
+- ntp