mattwire
--- a/Civi/UpdaterecurWorker.php
+++ b/Civi/UpdaterecurWorker.php
  public function changeSubscriptionAmount(array $changeActivity, array $recur, CRM_Core_Payment $paymentProcessorObject) :string {
    // Old (current, as of 5.49) method
    $message = '';
+    $newAmount = $changeActivity['updaterecur_activity_fields.updaterecur_new_amount'];
--- a/Civi/UpdaterecurWorker.php
+++ b/Civi/UpdaterecurWorker.php
  public function changeSubscriptionAmount(array $changeActivity, array $recur, CRM_Core_Payment $paymentProcessorObject) :string {
    // Old (current, as of 5.49) method
    $message = '';
+    $newAmount = $changeActivity['updaterecur_activity_fields.updaterecur_new_amount'];
+    // contributionRecurID is the "correct" parameter per propertyBag, but it wasn't well defined before 5.70
+    // so we need to pass in id as well as some PaymentProcessors will expect that.
+    // Older payment processors will still expect `subscriptionId` which is really processor_id but we don't support that.
    $paymentProcessorObject->changeSubscriptionAmount($message, [
+      'contributionRecurID' => $recur['id'],