diff --git a/inc/CalDAVRequest.php b/inc/CalDAVRequest.php
index e0963fae..01711e09 100644
--- a/inc/CalDAVRequest.php
+++ b/inc/CalDAVRequest.php
@@ -105,6 +105,11 @@ class CalDAVRequest
   */
   public $ticket;
 
+  /**
+   * Whether this request included the 'Brief: T' header.
+   */
+  public $brief_response;
+  
   /**
   * Create a new CalDAVRequest object.
   */
@@ -113,6 +118,8 @@ class CalDAVRequest
 
     $this->options = $options;
     if ( !isset($this->options['allow_by_email']) ) $this->options['allow_by_email'] = false;
+    
+    $this->brief_response = (isset($_SERVER['HTTP_BRIEF']) && (strtoupper($_SERVER['HTTP_BRIEF']) == 'T'));
 
     /**
     * Our path is /<script name>/<user name>/<user controlled> if it ends in
diff --git a/inc/DAVResource.php b/inc/DAVResource.php
index 9cff34da..f46c2420 100644
--- a/inc/DAVResource.php
+++ b/inc/DAVResource.php
@@ -1636,13 +1636,13 @@ EOQRY;
           if ( isset($this->dead_properties[$tag]) ) {
             $set_of_components = explode('"', $this->dead_properties[$tag]);
             foreach( $set_of_components AS $k => $v ) {
-              if ( !preg_match('{(VEVENT|VTODO|VJOURNAL|VTIMEZONE|VFREEBUSY)}', $v) ) {
+              if ( !preg_match('{(VEVENT|VTODO|VJOURNAL|VTIMEZONE|VFREEBUSY|VPOLL|VAVAILABILITY)}', $v) ) {
                 unset( $set_of_components[$k] );
               }
             }
           }
           else {
-            $set_of_components = array( 'VEVENT', 'VTODO', 'VJOURNAL', 'VTIMEZONE', 'VFREEBUSY' );
+            $set_of_components = array( 'VEVENT', 'VTODO', 'VJOURNAL', 'VTIMEZONE', 'VFREEBUSY', 'VPOLL', 'VAVAILABILITY' );
           }
         }
         else if ( $this->IsSchedulingCollection() )
@@ -1800,7 +1800,7 @@ EOQRY;
       $elements[] = new XMLElement( 'propstat', array( $noprop, $status) );
     }
 
-    if ( count($not_found) > 0 ) {
+    if ( !(isset($request->brief_response) && $request->brief_response) && count($not_found) > 0 ) {
       $status = new XMLElement('status', 'HTTP/1.1 404 Not Found' );
       $noprop = new XMLElement('prop');
       foreach( $not_found AS $k => $v ) {
diff --git a/inc/caldav-REPORT.php b/inc/caldav-REPORT.php
index 1652f1e4..1da78f1f 100644
--- a/inc/caldav-REPORT.php
+++ b/inc/caldav-REPORT.php
@@ -200,7 +200,7 @@ function component_to_xml( $properties, $item ) {
     $elements[] = new XMLElement( "propstat", array( $noprop, $status) );
   }
 
-  if ( count($unsupported) > 0 ) {
+  if ( !(isset($request->brief_response) && $request->brief_response) && count($unsupported) > 0 ) {
     $status = new XMLElement("status", "HTTP/1.1 404 Not Found" );
     $noprop = new XMLElement("prop");
     foreach( $unsupported AS $k => $v ) {