diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 7c229f59016f..2fb35658d151 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -116,7 +116,7 @@ ipfrag_high_thresh - LONG INTEGER
 	Maximum memory used to reassemble IP fragments.
 
 ipfrag_low_thresh - LONG INTEGER
-	(Obsolete since linux-4.17)
+	(Obsolete since linux-4.4.174, backported from linux-4.17)
 	Maximum memory used to reassemble IP fragments before the kernel
 	begins to remove incomplete fragment queues to free up resources.
 	The kernel still accepts new fragments for defragmentation.