diff --git a/CRM/Core/Payment/OmnipayMultiProcessor.php b/CRM/Core/Payment/OmnipayMultiProcessor.php
index d74a23395..cc63f9d44 100644
--- a/CRM/Core/Payment/OmnipayMultiProcessor.php
+++ b/CRM/Core/Payment/OmnipayMultiProcessor.php
@@ -141,9 +141,15 @@ public function doPayment(&$params, $component = 'contribute') {
       if (!empty($params['token'])) {
         $response = $this->doTokenPayment($params);
       }
-      elseif (!empty($params['is_recur'])) {
+      elseif (!empty($params['is_recur']) && (!$this->getProcessorTypeMetadata('continuous_authority'))) {
         $response = $this->gateway->createCard($this->getCreditCardOptions(array_merge($params, array('action' => 'Purchase')), $this->_component))->send();
       }
+      elseif ($params['continuous_authority_repeat'] && $this->getProcessorTypeMetadata('continuous_authority')) {
+        $repeat = $this->getCreditCardOptions($params);
+        unset($repeat['card']);
+        $repeat['transactionReference'] = $params['original_contribution_trxn_id'];
+        $response = $this->gateway->repeatAuthorize($repeat)->send();
+      }
       else {
         $response = $this->gateway->purchase($this->getCreditCardOptions($params))
           ->send();
@@ -176,6 +182,9 @@ public function doPayment(&$params, $component = 'contribute') {
         return $params;
       }
       elseif ($response->isRedirect()) {
+        if ($this->getProcessorTypeMetadata('notification_from_different_session')) {
+          $this->saveTransactionReference($params['contributionID'], $response);
+        }
         $isTransparentRedirect = ($response->isTransparentRedirect() || !empty($this->gateway->transparentRedirect));
         $this->cleanupClassForSerialization(TRUE);
         CRM_Core_Session::storeSessionObjects(FALSE);
@@ -202,6 +211,68 @@ public function doPayment(&$params, $component = 'contribute') {
     }
   }
 
+  /**
+   * Sagepay requires us remembering the transaction reference before redirecting,
+   * as it contains the `SecurityKey` field, that will be necessary in order
+   * to verify a successful payment notification.
+   *
+   * Also, their call to notify payments is made by Sagepay servers, not by
+   * the user who started the transaction. Therefore, as session variables
+   * are not going to be available, we need to store the `qfKey` also.
+   */
+  protected function saveTransactionReference($contributionID, $response) {
+    civicrm_api3('Contribution', 'create', [
+      'id' => $contributionID,
+      'trxn_id' => $this->addQfKeyToTransactionReference($response),
+    ]);
+  }
+
+  /**
+   * Save the qfKey as part of the transaction reference so it can be accessed
+   * from both sessions: the user one and the Sagepay notification service.
+   */
+  protected function addQfKeyToTransactionReference($response) {
+    try {
+      $reference = json_decode($response->getTransactionReference(), TRUE);
+    } catch(Exception $e) {}
+
+    $reference['qfKey'] = $this->getQfKey();
+    return json_encode($reference);
+  }
+
+  /**
+   * During Sagepay payment notifications, we need to read both the
+   * `SecurityKey` and the `qfKey` from the database. The first one
+   * to actually validate the notification. The second one to obtain
+   * the redirection URLs.
+   */
+  protected function getSavedParameter($contributionID, $field) {
+    $trxnId = CRM_Core_DAO::singleValueQuery('SELECT trxn_id
+      FROM civicrm_contribution
+      WHERE id = %1', [
+        1 => [ $contributionID, 'Integer' ]
+      ]
+    );
+
+    if ($trxnId) {
+      try {
+        $reference = json_decode($trxnId, TRUE);
+      } catch(Exception $e) {}
+
+      if (array_key_exists($field, $reference)) {
+        return $reference[$field];
+      }
+    }
+  }
+
+  protected function getSavedSecurityKey($contributionID) {
+    return $this->getSavedParameter($contributionID, 'SecurityKey');
+  }
+
+  protected function getSavedQfKey($contributionID) {
+    return $this->getSavedParameter($contributionID, 'qfKey');
+  }
+
   /**
    * Initialize class variables.
    *
@@ -512,6 +583,8 @@ private function getCreditCardObjectParams($params) {
       $cardFields['billingState'] = CRM_Core_PseudoConstant::stateProvinceAbbreviation($cardFields['billingState']);
     }
 
+    $this->copyShippingFieldsFromBillingIfEmpty($cardFields);
+
     if (empty($cardFields['email'])) {
       if (!empty($params['email-' . $billingID])) {
         $cardFields['email'] = $params['email-' . $billingID];
@@ -530,6 +603,21 @@ private function getCreditCardObjectParams($params) {
     return $cardFields;
   }
 
+  /**
+   * To prevent errors like Sagepay's "3140 : The DeliveryCountry value is invalid",
+   * we copy billing values where shipping values are empty
+   */
+  protected function copyShippingFieldsFromBillingIfEmpty(&$cardFields) {
+    $fieldSuffixes = [ 'Address1', 'Address2', 'City', 'Postcode', 'State', 'Country' ];
+    foreach($fieldSuffixes as $fieldSuffix) {
+      $billingField = 'billing' . $fieldSuffix;
+      $shippingField = 'shipping' . $fieldSuffix;
+      if (empty($cardFields[$shippingField]) && isset($cardFields[$billingField])) {
+        $cardFields[$shippingField] = $cardFields[$billingField];
+      }
+    }
+  }
+
   /**
    * Get sensitive credit card fields.
    *
@@ -737,6 +825,24 @@ public function getBillingAddressFields($billingLocationID = NULL) {
     return $billingFields;
   }
 
+  /**
+   * Get details of CiviCRM mandatory and optional address fields.
+   *
+   * @param int $billingLocationID
+   *
+   * @return array
+   */
+  public function getBillingAddressFieldsMetadata($billingLocationID = NULL) {
+    $metadata = parent::getBillingAddressFieldsMetadata($billingLocationID);
+    $fields = $this->getProcessorTypeMetadata('fields');
+    $fieldDetails = $this->getProcessorTypeMetadata('field_details');
+    foreach($fieldDetails as $key => $value) {
+      $metaKey = $fields['billing_fields'][$key];
+      $metadata[$metaKey] = array_merge($metadata[$metaKey], $value);
+    }
+    return $metadata;
+  }
+
   /**
    * Handle response from processor.
    *
@@ -781,6 +887,13 @@ public function processPaymentNotification($params) {
         $response = $this->gateway->completePurchase($params)->send();
       }
       if ($response->getTransactionId()) {
+        if ($this->getProcessorTypeMetadata('notification_from_different_session')) {
+          $this->setQfKey($this->getSavedQfKey($response->getTransactionId()));
+          $securityKey = $this->getSavedSecurityKey($response->getTransactionId());
+          if ($securityKey) {
+            $response->setSecurityKey($securityKey);
+          }
+        }
         $this->setContributionReference($response->getTransactionId(), 'strip');
       }
     }
@@ -808,9 +921,14 @@ public function processPaymentNotification($params) {
         ));
 
         if ($this->getLock() && CRM_Core_PseudoConstant::getName('CRM_Contribute_BAO_Contribution', 'contribution_status_id', $contribution['contribution_status_id']) !== 'Completed') {
+          if ($this->getProcessorTypeMetadata('notification_from_different_session')) {
+            $reference = $this->addQfKeyToTransactionReference($response);
+          } else {
+            $reference = $response->getTransactionReference();
+          }
           civicrm_api3('contribution', 'completetransaction', array(
             'id' => $this->transaction_id,
-            'trxn_id' => $response->getTransactionReference(),
+            'trxn_id' => $reference,
             'payment_processor_id' => $params['processor_id'],
           ));
         }
@@ -931,7 +1049,12 @@ protected function redirectOrExit($outcome, $response = NULL) {
         CRM_Core_Session::setStatus($userMsg);
         $redirectUrl = $this->getStoredUrl('fail');
         if (!$redirectUrl && method_exists($response, 'invalid')) {
-          $response->invalid($redirectUrl, $userMsg);
+          if ($this->getProcessorTypeMetadata('notification_from_different_session')) {
+            $qfKey = $this->getSavedQfKey($this->transaction_id);
+            $response->invalid($this->getReturnFailUrl($qfKey), $userMsg);
+          } else {
+            $response->invalid($redirectUrl, $userMsg);
+          }
         }
         break;
 
@@ -943,7 +1066,12 @@ protected function redirectOrExit($outcome, $response = NULL) {
         CRM_Core_Session::setStatus($userMsg);
         $redirectUrl = $this->getStoredUrl('fail');
         if ($response && method_exists($response, 'error')) {
-          $response->error($redirectUrl, $userMsg);
+          if ($this->getProcessorTypeMetadata('notification_from_different_session')) {
+            $qfKey = $this->getSavedQfKey($this->transaction_id);
+            $response->error($this->getReturnFailUrl($qfKey), $userMsg);
+          } else {
+            $response->error($redirectUrl, $userMsg);
+          }
         }
         try {
           $this->handleError('error', $this->transaction_id . ' ' . $response->getMessage(), array('processor_error', $response->getMessage()), 9002, $userMsg);
@@ -956,7 +1084,12 @@ protected function redirectOrExit($outcome, $response = NULL) {
         $userMsg = NULL;
         $redirectUrl = $this->getStoredUrl('success');
         if (!$redirectUrl && method_exists($response, 'confirm')) {
-          $output = $response->confirm($redirectUrl, $userMsg);
+          if ($this->getProcessorTypeMetadata('notification_from_different_session')) {
+            $qfKey = $this->getSavedQfKey($this->transaction_id);
+            $response->confirm($this->getReturnSuccessUrl($qfKey), $userMsg);
+          } else {
+            $output = $response->confirm($redirectUrl, $userMsg);
+          }
           if ($output) {
             echo $output;
           }
diff --git a/Metadata/omnipay_Sagepay_Server.mgd.php b/Metadata/omnipay_Sagepay_Server.mgd.php
index 5af7605e2..587a66880 100644
--- a/Metadata/omnipay_Sagepay_Server.mgd.php
+++ b/Metadata/omnipay_Sagepay_Server.mgd.php
@@ -56,7 +56,14 @@
             'postal_code' => "billing_postal_code-{$billingLocationID}",
           ),
         ),
+        'field_details' => array(
+          'state_province' => array(
+            'is_required' => FALSE,
+          )
+        ),
         'ipn_processing_delay' => 0,
+        'notification_from_different_session' => TRUE,
+        'continuous_authority' => TRUE,
       ),
       'params' =>
         array(
@@ -67,10 +74,13 @@
           'user_name_label' => 'Vendor',
           'password_label' => 'unused',
           'signature_label' => 'unused',
-          'site_url' => '',
+          'site_url' => 'unused',
           'class_name' => 'Payment_OmnipayMultiProcessor',
           'billing_mode' => 4,
           'payment_type' => 3,
+          'url_recur_default' => 'http://unused.com',
+          'url_recur_test_default' => 'http://unused.com',
+          'is_recur' => 0,
         ),
     ),
 );
diff --git a/api/v3/Job/ProcessRecurring.php b/api/v3/Job/ProcessRecurring.php
index 3f8ad0ab3..28d0c4bff 100644
--- a/api/v3/Job/ProcessRecurring.php
+++ b/api/v3/Job/ProcessRecurring.php
@@ -35,29 +35,51 @@ function civicrm_api3_job_process_recurring($params) {
         'is_email_receipt' => FALSE,
       ));
 
-      $payment = civicrm_api3('PaymentProcessor', 'pay', array(
-        'amount' => $originalContribution['total_amount'],
-        'currency' => $originalContribution['currency'],
-        'payment_processor_id' => $paymentProcessorID,
-        'contributionID' => $pending['id'],
-        'contribution_id' => $pending['id'],
-        'contactID' => $originalContribution['contact_id'],
-        'description' => ts('Repeat payment, original was ' . $originalContribution['id']),
-        'token' => civicrm_api3('PaymentToken', 'getvalue', [
-          'id' => $recurringPayment['payment_token_id'],
-          'return' => 'token',
-        ]),
-        'payment_action' => 'purchase',
-      ));
-      $payment = reset($payment['values']);
+      if (!is_continuous_authority($omnipayProcessors['values'][$paymentProcessorID])) {
+        $payment = civicrm_api3('PaymentProcessor', 'pay', array(
+          'amount' => $originalContribution['total_amount'],
+          'currency' => $originalContribution['currency'],
+          'payment_processor_id' => $paymentProcessorID,
+          'contributionID' => $pending['id'],
+          'contribution_id' => $pending['id'],
+          'contactID' => $originalContribution['contact_id'],
+          'description' => ts('Repeat payment, original was ' . $originalContribution['id']),
+          'token' => civicrm_api3('PaymentToken', 'getvalue', [
+            'id' => $recurringPayment['payment_token_id'],
+            'return' => 'token',
+          ]),
+          'payment_action' => 'purchase',
+        ));
+        $payment = reset($payment['values']);
 
-      civicrm_api3('Contribution', 'completetransaction', array(
-        'id' => $pending['id'],
-        'trxn_id' => $payment['trxn_id'],
-        'payment_processor_id' => $paymentProcessorID,
-      ));
-      $result['success']['ids'] = $recurringPayment['id'];
+        civicrm_api3('Contribution', 'completetransaction', array(
+          'id' => $pending['id'],
+          'trxn_id' => $payment['trxn_id'],
+          'payment_processor_id' => $paymentProcessorID,
+        ));
+        $result['success']['ids'] = $recurringPayment['id'];
+      } else {
+        $payment = civicrm_api3('PaymentProcessor', 'pay', array(
+          'amount' => $originalContribution['total_amount'],
+          'currency' => $originalContribution['currency'],
+          'payment_processor_id' => $paymentProcessorID,
+          'contributionID' => $pending['id'],
+          'contribution_id' => $pending['id'],
+          'original_contribution_trxn_id' => $originalContribution['trxn_id'],
+          'continuous_authority_repeat' => TRUE,
+          'contactID' => $originalContribution['contact_id'],
+          'description' => ts('Repeat payment, original was ' . $originalContribution['id']),
+          'payment_action' => 'purchase',
+        ));
+        $payment = reset($payment['values']);
 
+        civicrm_api3('Contribution', 'completetransaction', array(
+          'id' => $pending['id'],
+          'trxn_id' => $payment['trxn_id'],
+          'payment_processor_id' => $paymentProcessorID,
+        ));
+        $result['success']['ids'] = $recurringPayment['id'];
+      }
     }
     catch (CiviCRM_API3_Exception $e) {
       // Failed - what to do?
@@ -84,3 +106,44 @@ function civicrm_api3_job_process_recurring($params) {
  */
 function _civicrm_api3_job_process_recurring_spec(&$params) {
 }
+
+function is_continuous_authority($paymentProcessor) {
+  $paymentProcessorType = civicrm_api3('PaymentProcessorType', 'get', array(
+    'id' => $paymentProcessor['payment_processor_type_id'],
+    'sequential' => 1,
+  ));
+
+  $property = get_processor_type_property($paymentProcessorType['values'][0]['name'], 'continuous_authority');
+
+  if($property['found']) {
+    return $property['value'];
+  } else {
+    return FALSE;
+  }
+}
+
+function get_processor_type_by_name($processorTypeName, $entity) {
+  if($entity['entity'] != 'payment_processor_type') { return FALSE; }
+  if(!array_key_exists('params', $entity)) { return FALSE; }
+  if(!array_key_exists('name', $entity['params'])) { return FALSE; }
+  return $entity['params']['name'] == $processorTypeName;
+}
+
+function get_processor_type_metadata($processorTypeName) {
+  $entities = [];
+  omnipaymultiprocessor_civicrm_managed($entities);
+  $filter_by_name = function($entity) use($processorTypeName) {
+    return get_processor_type_by_name($processorTypeName, $entity);
+  };
+  return array_values(array_filter($entities, $filter_by_name))[0];
+}
+
+function get_processor_type_property($processorTypeName, $propertyName) {
+  $processorTypeMetadata = get_processor_type_metadata($processorTypeName);
+  if(!array_key_exists('metadata', $processorTypeMetadata)) { return array('found' => FALSE); }
+  if(!array_key_exists($propertyName, $processorTypeMetadata['metadata'])) { return array('found' => FALSE); }
+  return array(
+    'found' => TRUE,
+    'value' => $processorTypeMetadata['metadata'][$propertyName],
+  );
+}