diff --git a/share/man/man9/spl.9 b/share/man/man9/spl.9
index 6a295e8178ec..fe4bec27f575 100644
--- a/share/man/man9/spl.9
+++ b/share/man/man9/spl.9
@@ -74,6 +74,15 @@ Use mutexes to protect data structures instead.
 See
 .Xr mutex 9
 for more information.
+The API is now a complete NOP.
+This man page documents historical behavior so you can understand the
+code locking that the spl did when converting code from versions of the
+kernel prior to
+.Fx 5.0 .
+The examples in this man page are also obsolete and should not be viewed
+as documenting 
+.Fx 5.0 
+and newer.
 .Ef
 .Pp
 The
@@ -211,6 +220,9 @@ sets of functions to be blocked during some periods of the life of
 the system.
 The historical number scheme can be considered as a
 simple linearly ordered set of interrupt priority groups.
+.Pp
+.Fx 5.0 eliminated spl entirely in favor of locking primitives which scale
+to more than one processor.
 .Sh AUTHORS
 This manual page was written by
 .An J\(:org Wunsch .