diff --git a/reference/pthreads/modifiers.xml b/reference/pthreads/modifiers.xml
index 3495d568af..c1b0ab5e6a 100644
--- a/reference/pthreads/modifiers.xml
+++ b/reference/pthreads/modifiers.xml
@@ -4,6 +4,11 @@
 <chapter xml:id="pthreads.modifiers" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
  <title>Method Modifiers</title>
  <titleabbrev>Modifiers</titleabbrev>
+ <warning>
+   <para>
+    These semantics are only applicable to pthreads v2 - they have been removed in pthreads v3.
+   </para>
+  </warning>
  <para>
   pthreads overrides the functionality of the protected and private method modifiers in order to provide functionality more suited to multi-threaded objects.
   pthreads applies this functionality to all Threaded objects from creation.