diff --git a/NEWS b/NEWS
index 2f97331f..64651ea0 100644
--- a/NEWS
+++ b/NEWS
@@ -9,6 +9,8 @@ NEWS ( CHANGELOG and HISTORY )                                     HTMLPurifier
     . Internal change
 ==========================
 
+2.1-strict branch was fully obsoleted by release of 3.0.0. It is no longer supported.
+
 2.1.3, released 2007-11-05
 ! tests/multitest.php allows you to test multiple versions by running
   tests/index.php through multiple interpreters using `phpv` shell
diff --git a/OBSOLETE b/OBSOLETE
new file mode 100644
index 00000000..ed4d16d4
--- /dev/null
+++ b/OBSOLETE
@@ -0,0 +1,2 @@
+2.1-strict branch was fully obsoleted by release of 3.0.0. It is no longer
+supported. Bug and security fixes will not be issued regardless of security.
\ No newline at end of file