diff --git a/htdocs/caldav.php b/htdocs/caldav.php
index 98ded38f..5a7ba7d3 100644
--- a/htdocs/caldav.php
+++ b/htdocs/caldav.php
@@ -118,6 +118,7 @@ switch ( $request_method ) {
   case 'OPTIONS':    include_once("caldav-OPTIONS.php");    break;
   case 'REPORT':     include_once("caldav-REPORT.php");     break;
   case 'PROPFIND':   include_once("caldav-PROPFIND.php");   break;
+  case 'PROPPATCH':  include_once("caldav-PROPPATCH.php");  break;
   case 'MKCALENDAR': include_once("caldav-MKCALENDAR.php"); break;
   case 'MKCOL':      include_once("caldav-MKCOL.php");      break;
   case 'PUT':        include_once("caldav-PUT.php");        break;
diff --git a/inc/caldav-OPTIONS.php b/inc/caldav-OPTIONS.php
index 780742ed..82a37fe2 100644
--- a/inc/caldav-OPTIONS.php
+++ b/inc/caldav-OPTIONS.php
@@ -62,7 +62,7 @@ if ( !exists ) {
   * PROPPATCH, because I suspect that will be used.  Also HEAD and POST being fairly standard
   * should be handled.  COPY and MOVE would seem to be easy also.
   */
-  $allowed = "OPTIONS, GET, PUT, DELETE, PROPFIND, MKCOL, MKCALENDAR";
+  $allowed = "OPTIONS, GET, PUT, DELETE, PROPFIND, PROPPATCH, MKCOL, MKCALENDAR";
   if ( $is_calendar ) $allowed .= ", REPORT";
   header( "Allow: $allowed");
   // header( "Allow: ACL, COPY, DELETE, GET, HEAD, LOCK, MKCALENDAR, MKCOL, MOVE, OPTIONS, POST, PROPFIND, PROPPATCH, PUT, REPORT, SCHEDULE, TRACE, UNLOCK");
diff --git a/inc/caldav-PROPPATCH.php b/inc/caldav-PROPPATCH.php
new file mode 100644
index 00000000..4adef33b
--- /dev/null
+++ b/inc/caldav-PROPPATCH.php
@@ -0,0 +1,7 @@
+<?php
+  echo "<h1>Unimplemented</h1><p>Unfortunately this function is planned, but not yet implemented</p";
+  echo "<p>Well, actually, perhaps 'planned' is too strong a word.  It <em>is</em> on the roadmap, and if you want to
+contribute to the planning, please add your two cents to the Sourceforge forums or tracker items.</p>";
+  echo "<p>It would also be useful if you could find a client which uses it, maybe even a log of it
+doing so, and so on.</p>";
+?>
\ No newline at end of file