diff --git a/tests/src/FunctionalJavascript/ContributionIatsTest.php b/tests/src/FunctionalJavascript/ContributionIatsTest.php
index 55bd1241a..7807ac423 100644
--- a/tests/src/FunctionalJavascript/ContributionIatsTest.php
+++ b/tests/src/FunctionalJavascript/ContributionIatsTest.php
@@ -256,7 +256,7 @@ public function testSubmitContribution() {
     $this->assertSession()->waitForField('credit_card_number');
     $this->getSession()->getPage()->fillField('Card Number', '4222222222222220');
     $this->getSession()->getPage()->fillField('Security Code', '123');
-    $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[m]', '11');
+    $this->getSession()->getPage()->selectFieldOption($this->getCreditCardMonthFieldName(), '11');
     $this_year = date('Y');
     $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[Y]', $this_year + 1);
     $billingValues = [
@@ -463,7 +463,7 @@ public function testSubmitRecurringContribution() {
     $this->assertSession()->waitForField('credit_card_number');
     $this->getSession()->getPage()->fillField('Card Number', '4222222222222220');
     $this->getSession()->getPage()->fillField('Security Code', '123');
-    $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[m]', '11');
+    $this->getSession()->getPage()->selectFieldOption($this->getCreditCardMonthFieldName(), '11');
     $this_year = date('Y');
     $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[Y]', $this_year + 1);
     $billingValues = [
@@ -529,7 +529,7 @@ public function testSubmitRecurringContribution() {
     $this->assertSession()->waitForField('credit_card_number');
     $this->getSession()->getPage()->fillField('Card Number', '4222222222222220');
     $this->getSession()->getPage()->fillField('Security Code', '123');
-    $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[m]', '11');
+    $this->getSession()->getPage()->selectFieldOption($this->getCreditCardMonthFieldName(), '11');
     $this_year = date('Y');
     $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[Y]', $this_year + 1);
     $billingValues = [
diff --git a/tests/src/FunctionalJavascript/EventTest.php b/tests/src/FunctionalJavascript/EventTest.php
index 068c58d82..7ff9de9a2 100644
--- a/tests/src/FunctionalJavascript/EventTest.php
+++ b/tests/src/FunctionalJavascript/EventTest.php
@@ -189,7 +189,7 @@ function testSubmitEventParticipant() {
     $this->assertSession()->waitForField('credit_card_number');
     $this->getSession()->getPage()->fillField('Card Number', '4222222222222220');
     $this->getSession()->getPage()->fillField('Security Code', '123');
-    $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[m]', '11');
+    $this->getSession()->getPage()->selectFieldOption($this->getCreditCardMonthFieldName(), '11');
     $this_year = date('Y');
     $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[Y]', $this_year + 1);
     $billingValues = [
diff --git a/tests/src/FunctionalJavascript/MembershipSubmissionTest.php b/tests/src/FunctionalJavascript/MembershipSubmissionTest.php
index df126cca8..0287a4421 100644
--- a/tests/src/FunctionalJavascript/MembershipSubmissionTest.php
+++ b/tests/src/FunctionalJavascript/MembershipSubmissionTest.php
@@ -63,7 +63,7 @@ function testSubmitMembershipAutoRenew() {
     $this->assertSession()->waitForField('credit_card_number');
     $this->getSession()->getPage()->fillField('Card Number', '4222222222222220');
     $this->getSession()->getPage()->fillField('Security Code', '123');
-    $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[m]', '11');
+    $this->getSession()->getPage()->selectFieldOption($this->getCreditCardMonthFieldName(), '11');
     $this_year = date('Y');
     $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[Y]', $this_year + 1);
     $billingValues = [
diff --git a/tests/src/FunctionalJavascript/MultiCustomFieldsSubmissionTest.php b/tests/src/FunctionalJavascript/MultiCustomFieldsSubmissionTest.php
index a654a808f..9da9d6cdd 100644
--- a/tests/src/FunctionalJavascript/MultiCustomFieldsSubmissionTest.php
+++ b/tests/src/FunctionalJavascript/MultiCustomFieldsSubmissionTest.php
@@ -152,7 +152,7 @@ public function testAnonymousSubmitWithContribution() {
 
     $this->getSession()->getPage()->fillField('Card Number', '4222222222222220');
     $this->getSession()->getPage()->fillField('Security Code', '123');
-    $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[m]', '11');
+    $this->getSession()->getPage()->selectFieldOption($this->getCreditCardMonthFieldName(), '11');
     $this_year = date('Y');
     $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[Y]', $this_year + 1);
     $this->getSession()->getPage()->pressButton('Submit');
diff --git a/tests/src/FunctionalJavascript/WebformCivicrmTestBase.php b/tests/src/FunctionalJavascript/WebformCivicrmTestBase.php
index 9631e6936..e9376fb57 100644
--- a/tests/src/FunctionalJavascript/WebformCivicrmTestBase.php
+++ b/tests/src/FunctionalJavascript/WebformCivicrmTestBase.php
@@ -720,7 +720,7 @@ protected function fillCardAndSubmit($billingValues = []) {
     $this->assertSession()->waitForField('credit_card_number');
     $this->getSession()->getPage()->fillField('credit_card_number', '4222222222222220');
     $this->getSession()->getPage()->fillField('cvv2', '123');
-    $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[m]', '11');
+    $this->getSession()->getPage()->selectFieldOption($this->getCreditCardMonthFieldName(), '11');
     $this_year = date('Y');
     $this->getSession()->getPage()->selectFieldOption('credit_card_exp_date[Y]', $this_year + 1);
 
@@ -804,4 +804,14 @@ protected function getLastSubmissionId(WebformInterface $webform) {
     return reset($submission_ids);
   }
 
+  /**
+   * Can remove this once only testing 5.65+
+   */
+  private function getCreditCardMonthFieldName(): string {
+    if (version_compare(\CRM_Core_BAO_Domain::version(), '5.65.alpha1', '<')) {
+      return 'credit_card_exp_date[M]';
+    }
+    return 'credit_card_exp_date[m]';
+  }
+
 }