diff --git a/lib/form/classes/filetypes_util.php b/lib/form/classes/filetypes_util.php
index fb74b3f7f56..6dc4c74ea8d 100644
--- a/lib/form/classes/filetypes_util.php
+++ b/lib/form/classes/filetypes_util.php
@@ -68,7 +68,7 @@ class filetypes_util {
 
         // Turn string into a list.
         if (!is_array($types)) {
-            $types = preg_split('/[\s,;:"\']+/', $types, null, PREG_SPLIT_NO_EMPTY);
+            $types = preg_split('/[\s,;:"\']+/', $types, -1, PREG_SPLIT_NO_EMPTY);
         }
 
         // Fix whitespace and normalize the syntax a bit.
diff --git a/lib/tests/messageinbound_test.php b/lib/tests/messageinbound_test.php
index ab70d2cb3ea..5b5190f5409 100644
--- a/lib/tests/messageinbound_test.php
+++ b/lib/tests/messageinbound_test.php
@@ -116,7 +116,7 @@ class messageinbound_test extends \advanced_testcase {
         $content = file_get_contents($file->getRealPath());
         $content = preg_replace("#\r\n#", "\n", $content);
         $tokens = preg_split('#(?:^|\n*)----([A-Z]+)----\n#', $content,
-                null, PREG_SPLIT_DELIM_CAPTURE);
+                -1, PREG_SPLIT_DELIM_CAPTURE);
         $sections = array(
             // Key              => Required.
             'FULLSOURCE'        => true,
diff --git a/mod/workshop/locallib.php b/mod/workshop/locallib.php
index fd687c31e04..f6dc727c323 100644
--- a/mod/workshop/locallib.php
+++ b/mod/workshop/locallib.php
@@ -453,7 +453,7 @@ class workshop {
         }
 
         if (!is_array($extensions)) {
-            $extensions = preg_split('/[\s,;:"\']+/', $extensions, null, PREG_SPLIT_NO_EMPTY);
+            $extensions = preg_split('/[\s,;:"\']+/', $extensions, -1, PREG_SPLIT_NO_EMPTY);
         }
 
         foreach ($extensions as $i => $extension) {
diff --git a/question/type/gapselect/questiontypebase.php b/question/type/gapselect/questiontypebase.php
index 0d89c0d8a2c..77ecdb820cd 100644
--- a/question/type/gapselect/questiontypebase.php
+++ b/question/type/gapselect/questiontypebase.php
@@ -182,7 +182,7 @@ abstract class qtype_gapselect_base extends question_type {
         // Break up the question text, and store the fragments, places and right answers.
 
         $bits = preg_split('/\[\[(\d+)]]/', $question->questiontext,
-                null, PREG_SPLIT_DELIM_CAPTURE);
+                -1, PREG_SPLIT_DELIM_CAPTURE);
         $question->textfragments[0] = array_shift($bits);
         $i = 1;
 
diff --git a/question/type/multianswer/questiontype.php b/question/type/multianswer/questiontype.php
index d750bfd4e42..52ca37d5f13 100644
--- a/question/type/multianswer/questiontype.php
+++ b/question/type/multianswer/questiontype.php
@@ -281,7 +281,7 @@ class qtype_multianswer extends question_type {
         parent::initialise_question_instance($question, $questiondata);
 
         $bits = preg_split('/\{#(\d+)\}/', $question->questiontext,
-                null, PREG_SPLIT_DELIM_CAPTURE);
+                -1, PREG_SPLIT_DELIM_CAPTURE);
         $question->textfragments[0] = array_shift($bits);
         $i = 1;
         while (!empty($bits)) {