diff --git a/CRM/Core/BAO/RecurringEntity.php b/CRM/Core/BAO/RecurringEntity.php
index daf86a7806e7..67648230068b 100644
--- a/CRM/Core/BAO/RecurringEntity.php
+++ b/CRM/Core/BAO/RecurringEntity.php
@@ -31,7 +31,7 @@
  * @copyright CiviCRM LLC (c) 2004-2019
  */
 
-require_once 'packages/When/When.php';
+use When\When;
 
 /**
  * Class CRM_Core_BAO_RecurringEntity.
@@ -240,7 +240,7 @@ public function generate() {
    */
   public function generateRecursion() {
     // return if already generated
-    if (is_a($this->recursion, 'When')) {
+    if (is_a($this->recursion, 'When\When')) {
       return $this->recursion;
     }
 
@@ -334,7 +334,7 @@ public function generateRecursiveDates() {
     $this->generateRecursion();
 
     $recursionDates = [];
-    if (is_a($this->recursion, 'When')) {
+    if (is_a($this->recursion, 'When\When')) {
       $initialCount = CRM_Utils_Array::value('start_action_offset', $this->schedule);
 
       $exRangeStart = $exRangeEnd = NULL;
@@ -343,8 +343,12 @@ public function generateRecursiveDates() {
         $exRangeEnd = $this->excludeDateRangeColumns[1];
       }
 
+      if (CRM_Core_Config::singleton()->userFramework == 'UnitTests') {
+        $this->recursion->RFC5545_COMPLIANT = When::IGNORE;
+      }
       $count = 1;
-      while ($result = $this->recursion->next()) {
+      $result = $this->recursion_start_date;
+      while ($result = $this->getNextOccurrence($result)) {
         $skip = FALSE;
         if ($result == $this->recursion_start_date) {
           // skip the recursion-start-date from the list we going to generate
@@ -1004,14 +1008,14 @@ public function getRecursionFromSchedule($scheduleReminderDetails = []) {
       }
       $start = new DateTime($currDate);
       $this->recursion_start_date = $start;
-      if ($scheduleReminderDetails['repetition_frequency_unit']) {
-        $repetition_frequency_unit = $scheduleReminderDetails['repetition_frequency_unit'];
-        if ($repetition_frequency_unit == "day") {
-          $repetition_frequency_unit = "dai";
-        }
-        $repetition_frequency_unit = $repetition_frequency_unit . 'ly';
-        $r->recur($start, $repetition_frequency_unit);
+      $repetition_frequency_unit = $scheduleReminderDetails['repetition_frequency_unit'];
+      if ($repetition_frequency_unit == "day") {
+        $repetition_frequency_unit = "dai";
       }
+      $repetition_frequency_unit = $repetition_frequency_unit . 'ly';
+      $r->startDate($start)
+        ->exclusions([$start])
+        ->freq($repetition_frequency_unit);
 
       if ($scheduleReminderDetails['repetition_frequency_interval']) {
         $r->interval($scheduleReminderDetails['repetition_frequency_interval']);
@@ -1258,4 +1262,22 @@ public static function updateModeAndPriceSet($entityId, $entityTable, $mode, $li
     return $finalResult;
   }
 
+  /**
+   * Get next occurrence for the given date
+   *
+   * @param \DateTime $occurDate
+   * @param bool $strictly_after
+   *
+   * @return bool
+   */
+  private function getNextOccurrence($occurDate, $strictly_after = TRUE) {
+    try {
+      return $this->recursion->getNextOccurrence($occurDate, $strictly_after);
+    }
+    catch (Exception $exception) {
+      CRM_Core_Session::setStatus(ts($exception->getMessage()));
+    }
+    return FALSE;
+  }
+
 }
diff --git a/composer.json b/composer.json
index 42578e4e90e2..69eb155eadd9 100644
--- a/composer.json
+++ b/composer.json
@@ -64,7 +64,8 @@
     "pear/log": "1.13.1",
     "katzien/php-mime-type": "2.1.0",
     "civicrm/composer-downloads-plugin": "^2.0",
-    "league/csv": "^9.2"
+    "league/csv": "^9.2",
+    "tplaner/when": "dev-master#c1ec099f421bff354cc5c929f83b94031423fc80"
   },
   "require-dev": {
     "cache/integration-tests": "dev-master"
diff --git a/composer.lock b/composer.lock
index 9f5328a8ba4e..78a349252e21 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "f0b735ec69179cc1b69b87e335db9c7b",
+    "content-hash": "0ac00e2168797fa522d7a6f036a5e296",
     "packages": [
         {
             "name": "civicrm/civicrm-cxn-rpc",
@@ -2228,6 +2228,53 @@
             "homepage": "https://github.com/totten/ca_config",
             "time": "2017-05-10T20:08:17+00:00"
         },
+        {
+            "name": "tplaner/when",
+            "version": "dev-master",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/tplaner/When.git",
+                "reference": "c1ec099f421bff354cc5c929f83b94031423fc80"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/tplaner/When/zipball/c1ec099f421bff354cc5c929f83b94031423fc80",
+                "reference": "c1ec099f421bff354cc5c929f83b94031423fc80",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "^4.0"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "When\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Tom Planer",
+                    "email": "tplaner@gmail.com"
+                }
+            ],
+            "description": "Date/Calendar recursion library.",
+            "homepage": "https://github.com/tplaner/When",
+            "keywords": [
+                "date",
+                "datetime",
+                "recurrence",
+                "repeat",
+                "time"
+            ],
+            "time": "2019-01-11T21:59:13+00:00"
+        },
         {
             "name": "zendframework/zend-escaper",
             "version": "2.4.13",
@@ -2708,6 +2755,7 @@
     "stability-flags": {
         "zetacomponents/mail": 20,
         "pear/validate_finance_creditcard": 20,
+        "tplaner/when": 20,
         "cache/integration-tests": 20
     },
     "prefer-stable": false,
diff --git a/tests/phpunit/CRM/Core/BAO/RecurringEntityTest.php b/tests/phpunit/CRM/Core/BAO/RecurringEntityTest.php
index 4c0e6563a2be..008a05205520 100644
--- a/tests/phpunit/CRM/Core/BAO/RecurringEntityTest.php
+++ b/tests/phpunit/CRM/Core/BAO/RecurringEntityTest.php
@@ -75,10 +75,10 @@ public function testActivityGeneration() {
     $this->assertEquals(5, count($generatedEntities['civicrm_activity']), "Cehck if number of iterations are 5");
     $expectedDates = [
       '20141025103000',
-      '20141227103000',
-      '20150328103000',
-      '20150627103000',
-      '20150926103000',
+      '20150124103000',
+      '20150425103000',
+      '20150725103000',
+      '20151024103000',
     ];
     foreach ($generatedEntities['civicrm_activity'] as $entityID) {
       $this->assertDBNotNull('CRM_Activity_DAO_Activity', $entityID, 'id',