diff --git a/src/applications/maniphest/conduit/ManiphestGetTaskTransactionsConduitAPIMethod.php b/src/applications/maniphest/conduit/ManiphestGetTaskTransactionsConduitAPIMethod.php
--- a/src/applications/maniphest/conduit/ManiphestGetTaskTransactionsConduitAPIMethod.php
+++ b/src/applications/maniphest/conduit/ManiphestGetTaskTransactionsConduitAPIMethod.php
@@ -21,6 +21,16 @@
     return 'nonempty list<dict<string, wild>>';
   }
 
+  public function getMethodStatus() {
+    return self::METHOD_STATUS_FROZEN;
+  }
+
+  public function getMethodStatusDescription() {
+    return pht(
+      'This method is frozen and will eventually be deprecated. New code '.
+      'should use "transaction.search" instead.');
+  }
+
   protected function execute(ConduitAPIRequest $request) {
     $results = array();
     $task_ids = $request->getValue('ids');
diff --git a/src/applications/maniphest/xaction/ManiphestTaskPriorityTransaction.php b/src/applications/maniphest/xaction/ManiphestTaskPriorityTransaction.php
--- a/src/applications/maniphest/xaction/ManiphestTaskPriorityTransaction.php
+++ b/src/applications/maniphest/xaction/ManiphestTaskPriorityTransaction.php
@@ -6,20 +6,17 @@
   const TRANSACTIONTYPE = 'priority';
 
   public function generateOldValue($object) {
-    if ($this->isNewObject()) {
-      return null;
-    }
-    return $object->getPriority();
+    return (string)$object->getPriority();
   }
 
   public function generateNewValue($object, $value) {
     // `$value` is supposed to be a keyword, but if the priority
     // assigned to a task has been removed from the config,
     // no such keyword will be available. Other edits to the task
-    // should still be allowed, even if the priority is  no longer
+    // should still be allowed, even if the priority is no longer
     // valid, so treat this as a no-op.
     if ($value === ManiphestTaskPriority::UNKNOWN_PRIORITY_KEYWORD) {
-      return $object->getPriority();
+      return (string)$object->getPriority();
     }
 
     return (string)ManiphestTaskPriority::getTaskPriorityFromKeyword($value);
diff --git a/src/applications/maniphest/xaction/ManiphestTaskStatusTransaction.php b/src/applications/maniphest/xaction/ManiphestTaskStatusTransaction.php
--- a/src/applications/maniphest/xaction/ManiphestTaskStatusTransaction.php
+++ b/src/applications/maniphest/xaction/ManiphestTaskStatusTransaction.php
@@ -6,9 +6,6 @@
   const TRANSACTIONTYPE = 'status';
 
   public function generateOldValue($object) {
-    if ($this->isNewObject()) {
-      return null;
-    }
     return $object->getStatus();
   }