diff --git a/dba/caldav_functions.sql b/dba/caldav_functions.sql
index 8f6be8d1..f583afcb 100644
--- a/dba/caldav_functions.sql
+++ b/dba/caldav_functions.sql
@@ -1206,16 +1206,21 @@ DECLARE
   in_old_sync_token ALIAS FOR $1;
   in_collection_id ALIAS FOR $2;
   tmp_int INT8;
+  old_modification_time sync_tokens.modification_time%TYPE;
 BEGIN
   IF in_old_sync_token > 0 THEN
-    SELECT 1 INTO tmp_int FROM sync_changes
-            WHERE collection_id = in_collection_id
-              AND sync_time > (SELECT modification_time FROM sync_tokens WHERE sync_token = in_old_sync_token)
-            LIMIT 1;
+    SELECT modification_time INTO old_modification_time FROM sync_tokens WHERE sync_token = in_old_sync_token;
     IF NOT FOUND THEN
       -- They are in an inconsistent state: we return NULL so they can re-start the process
       RETURN NULL;
     END IF;
+    SELECT 1 INTO tmp_int FROM sync_changes WHERE collection_id = in_collection_id AND sync_time > old_modification_time LIMIT 1;
+    IF NOT FOUND THEN
+      -- Ensure we return the latest sync_token we have for this collection, since there are
+      -- no changes.
+	  SELECT sync_token INTO tmp_int FROM sync_tokens WHERE collection_id = in_collection_id ORDER BY modification_time DESC LIMIT 1;
+      RETURN tmp_int;
+    END IF;
   END IF;
   SELECT nextval('sync_tokens_sync_token_seq') INTO tmp_int;
   INSERT INTO sync_tokens(collection_id, sync_token) VALUES( in_collection_id, tmp_int );
diff --git a/inc/caldav-REPORT-sync-collection.php b/inc/caldav-REPORT-sync-collection.php
index 2bdb8e41..19f0820b 100644
--- a/inc/caldav-REPORT-sync-collection.php
+++ b/inc/caldav-REPORT-sync-collection.php
@@ -34,7 +34,10 @@ function display_status( $status_code ) {
 }
 
 $collection = new DAVResource( $request->path );
-
+if ( !$collection->Exists() ) {
+  $request->DoResponse( 404 );
+}
+  
 $params = array( ':collection_id' => $collection->GetProperty('collection_id'), ':sync_token' => $sync_token );
 $sql = "SELECT new_sync_token( :sync_token, :collection_id)";
 $qry = new AwlQuery($sql, $params);
@@ -45,7 +48,7 @@ $row = $qry->Fetch();
 
 if ( !isset($row->new_sync_token) ) {
   /** If we got a null back then they gave us a sync token we know not of, so provide a full sync */
-  $sync_token =0;
+  $sync_token = 0;
   $params[':sync_token'] = $sync_token;
   if ( !$qry->QDo($sql, $params) || $qry->rows() <= 0 ) {
     $request->DoResponse( 500, translate("Database error") );
@@ -54,85 +57,92 @@ if ( !isset($row->new_sync_token) ) {
 }
 $new_token = $row->new_sync_token;
 
-if ( $sync_token == 0 ) {
-  $sql = <<<EOSQL
-SELECT collection.*, calendar_item.*, caldav_data.*, addressbook_resource.*, 201 AS sync_status FROM collection
-            LEFT JOIN caldav_data USING (collection_id)
-            LEFT JOIN calendar_item USING (dav_id)
-                         LEFT JOIN addressbook_resource USING (dav_id)
-            WHERE collection.collection_id = :collection_id
-   ORDER BY collection.collection_id, caldav_data.dav_id
-EOSQL;
-  unset($params[':sync_token']);
-}
-else {
-  $sql = <<<EOSQL
-SELECT collection.*, calendar_item.*, caldav_data.*, addressbook_resource.*, sync_changes.*
-  FROM collection LEFT JOIN sync_changes USING(collection_id)
-                         LEFT JOIN caldav_data USING (collection_id,dav_id)
-                         LEFT JOIN calendar_item USING (collection_id,dav_id)
-                         LEFT JOIN addressbook_resource USING (dav_id)
-                         WHERE collection.collection_id = :collection_id
-       AND sync_time > (SELECT modification_time FROM sync_tokens WHERE sync_token = :sync_token)
-   ORDER BY collection.collection_id, sync_changes.dav_name, sync_changes.sync_time
-EOSQL;
-}
-$qry = new AwlQuery($sql, $params );
-
-$last_dav_name = '';
-$first_status = 0;
-
-if ( $qry->Exec("REPORT",__LINE__,__FILE__) ) {
-  while( $object = $qry->Fetch() ) {
-    if ( $object->dav_name == $last_dav_name ) {
-      /** The complex case: this is the second or subsequent for this dav_id */
-      if ( $object->sync_status == 404 ) {
-        array_pop($responses);
-        $resultset = array(
-          new XMLElement( 'href', ConstructURL($object->dav_name) ),
-          new XMLElement( 'status', display_status($object->sync_status) )
-        );
-        $responses[] = new XMLElement( 'sync-response', $resultset );
-        $first_status = 404;
-      }
-      else if ( $object->sync_status == 201 && $first_status == 404 ) {
-        // ... Delete ... Create ... is indicated as a create, but don't forget we started with a delete
-        array_pop($responses);
-        $resultset = array(
-          new XMLElement( 'href', ConstructURL($object->dav_name) ),
-          new XMLElement( 'status', display_status($object->sync_status) )
-        );
-        $dav_resource = new DAVResource($object);
-        $resultset = array_merge( $resultset, $dav_resource->GetPropStat($proplist,$reply) );
-        $responses[] = new XMLElement( 'sync-response', $resultset );
-      }
-      /** Else:
-       *    the object existed at start and we have multiple modifications,
-       *  or,
-       *    the object didn't exist at start and we have subsequent modifications,
-       *  but:
-       *    in either case we simply stick with our first report.
-       */
-    }
-    else {
-      /** The simple case: this is the first one for this dav_id */
-      $resultset = array(
-        new XMLElement( 'href', ConstructURL($object->dav_name) ),
-        new XMLElement( 'status', display_status($object->sync_status) )
-      );
-      $dav_resource = new DAVResource($object);
-      $resultset = array_merge( $resultset, $dav_resource->GetPropStat($proplist,$reply) );
-      $response_tag = 'response';
-      if ( isset($c->use_old_sync_response_tag) && $c->use_old_sync_response_tag ) $response_tag = 'sync-response';
-      $responses[] = new XMLElement( $response_tag, $resultset );
-      $first_status = $object->sync_status;
-      $last_dav_name  = $object->dav_name;
-    }
-  }
+if ( $sync_token == $new_token ) {
+  // No change, so we just re-send the old token.
   $responses[] = new XMLElement( 'sync-token', $new_token );
 }
 else {
-  $request->DoResponse( 500, translate("Database error") );
+  if ( $sync_token == 0 ) {
+    $sql = <<<EOSQL
+  SELECT collection.*, calendar_item.*, caldav_data.*, addressbook_resource.*, 201 AS sync_status FROM collection
+              LEFT JOIN caldav_data USING (collection_id)
+              LEFT JOIN calendar_item USING (dav_id)
+                           LEFT JOIN addressbook_resource USING (dav_id)
+              WHERE collection.collection_id = :collection_id
+     ORDER BY collection.collection_id, caldav_data.dav_id
+EOSQL;
+    unset($params[':sync_token']);
+  }
+  else {
+    $sql = <<<EOSQL
+  SELECT collection.*, calendar_item.*, caldav_data.*, addressbook_resource.*, sync_changes.*
+    FROM collection LEFT JOIN sync_changes USING(collection_id)
+                           LEFT JOIN caldav_data USING (collection_id,dav_id)
+                           LEFT JOIN calendar_item USING (collection_id,dav_id)
+                           LEFT JOIN addressbook_resource USING (dav_id)
+                           WHERE collection.collection_id = :collection_id
+         AND sync_time > (SELECT modification_time FROM sync_tokens WHERE sync_token = :sync_token)
+     ORDER BY collection.collection_id, sync_changes.dav_name, sync_changes.sync_time
+EOSQL;
+  }
+  $qry = new AwlQuery($sql, $params );
+ 
+  $last_dav_name = '';
+  $first_status = 0;
+  
+  if ( $qry->Exec("REPORT",__LINE__,__FILE__) ) {
+    while( $object = $qry->Fetch() ) {
+      if ( $object->dav_name == $last_dav_name ) {
+        /** The complex case: this is the second or subsequent for this dav_id */
+        if ( $object->sync_status == 404 ) {
+          array_pop($responses);
+          $resultset = array(
+            new XMLElement( 'href', ConstructURL($object->dav_name) ),
+            new XMLElement( 'status', display_status($object->sync_status) )
+          );
+          $responses[] = new XMLElement( 'sync-response', $resultset );
+          $first_status = 404;
+        }
+        else if ( $object->sync_status == 201 && $first_status == 404 ) {
+          // ... Delete ... Create ... is indicated as a create, but don't forget we started with a delete
+          array_pop($responses);
+          $dav_resource = new DAVResource($object);
+          $resultset = $dav_resource->GetPropStat($proplist,$reply);
+          array_unshift($resultset, new XMLElement( 'href', ConstructURL($object->dav_name)));
+          $responses[] = new XMLElement( 'response', $resultset );
+        }
+        /** Else:
+         *    the object existed at start and we have multiple modifications,
+         *  or,
+         *    the object didn't exist at start and we have subsequent modifications,
+         *  but:
+         *    in either case we simply stick with our existing report.
+         */
+      }
+      else {
+        /** The simple case: this is the first one for this dav_id */
+        if ( $object->sync_status == 404 ) {
+          $resultset = array(
+            new XMLElement( 'href', ConstructURL($object->dav_name) ),
+            new XMLElement( 'status', display_status($object->sync_status) )
+          );
+          $first_status = 404;
+        }
+        else {
+          $dav_resource = new DAVResource($object);
+          $resultset = $dav_resource->GetPropStat($proplist,$reply);
+          array_unshift($resultset, new XMLElement( 'href', ConstructURL($object->dav_name)));
+          $first_status = $object->sync_status;
+        }
+        $responses[] = new XMLElement( 'response', $resultset );
+        $last_dav_name  = $object->dav_name;
+      }
+    }
+    $responses[] = new XMLElement( 'sync-token', $new_token );
+  }
+  else {
+    $request->DoResponse( 500, translate("Database error") );
+  }
 }
 
 $multistatus = new XMLElement( "multistatus", $responses, $reply->GetXmlNsArray() );