git  diff MOODLE_311_STABLE_normalised master_normalised --ignore-all-space --ignore-blank-lines
diff --git a/.travis.yml b/.travis.yml
index a8fc7c32acc..0c565f37901 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -214,7 +214,7 @@ before_script:
         # We need the official upstream for comparison
         git remote add upstream https://github.com/moodle/moodle.git;

-        git fetch upstream MOODLE_311_STABLE;
+        git fetch upstream master;
         export GIT_PREVIOUS_COMMIT="`git merge-base FETCH_HEAD $TRAVIS_COMMIT`";
         export GIT_COMMIT="$TRAVIS_COMMIT";
         export UPSTREAM_FETCH_HEAD=`git rev-parse FETCH_HEAD`
diff --git a/analytics/classes/manager.php b/analytics/classes/manager.php
index 8bbdf4d2cd4..4216bbe4cfd 100644
--- a/analytics/classes/manager.php
+++ b/analytics/classes/manager.php
@@ -603,8 +603,8 @@ class manager {
      */
     public static function add_builtin_models() {

-        debugging('core_analytics\manager::add_builtin_models() has been deprecated. Core models are now automatically '.
-            'updated according to their declaration in the lib/db/analytics.php file.', DEBUG_DEVELOPER);
+        throw new \coding_exception('core_analytics\manager::add_builtin_models() has been removed. Core models ' .
+                        'are now automatically updated according to their declaration in the lib/db/analytics.php file.');
     }

     /**
diff --git a/analytics/upgrade.txt b/analytics/upgrade.txt
index 419613d83b1..b23200c73d7 100644
--- a/analytics/upgrade.txt
+++ b/analytics/upgrade.txt
@@ -5,6 +5,10 @@ information provided here is intended especially for developers.

 * Final deprecation get_enabled_time_splitting_methods. Method has been removed. Use
   get_time_splitting_methods_for_evaluation instead.
+* Final deprecation add_builtin_models. Method has been removed. The functionality
+  has been replaced with automatic update of models provided by the core moodle component.
+  There is no need to call this method explicitly any more. Instead, adding new models can be achieved
+  by updating the lib/db/analytics.php file and bumping the core version.
 * Final deprecation - get_analysables(). Please see get_analysables_interator() instead.
   get_analysables_iterator() needs to be overridden by the child class.

diff --git a/backup/backup.class.php b/backup/backup.class.php
index 0c0d1a7c424..4fdcb57c446 100644
--- a/backup/backup.class.php
+++ b/backup/backup.class.php
@@ -160,7 +160,7 @@ abstract class backup implements checksumable {
     /**
      * Usually same than major release zero version, mainly for informative/historic purposes.
      */
-    const RELEASE = '3.11';
+    const RELEASE = '4.0';

     /**
      * Cipher to be used in backup and restore operations.
diff --git a/composer.json b/composer.json
index 9e4adea7ba2..280cb4bb84a 100644
--- a/composer.json
+++ b/composer.json
@@ -6,7 +6,7 @@
     "homepage": "https://moodle.org",
     "require-dev": {
         "phpunit/phpunit": "8.5.*",
-        "moodlehq/behat-extension": "3.311.4",
+        "moodlehq/behat-extension": "3.400.4",
         "mikey179/vfsstream": "^1.6"
     },
     "minimum-stability": "dev",
diff --git a/composer.lock b/composer.lock
index 4a5f1d996c5..6c860fed808 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": "9fcac5e866795f6exd23c6114",
+    "content-hash": "fc0e25b3b9cf3308da4db2e1c6f1eb31",
     "packages": [],
     "packages-dev": [
         {
@@ -834,7 +834,7 @@
         },
         {
             "name": "moodlehq/behat-extension",
-            "version": "v3.311.4",
+            "version": "v3.400.4",
             "source": {
                 "type": "git",
                 "url": "https://github.com/moodlehq/moodle-behat-extension.git",
diff --git a/install/lang/el/install.php b/install/lang/el/install.php
index 1bd73e0a654..162a14453c8 100644
--- a/install/lang/el/install.php
+++ b/install/lang/el/install.php
@@ -84,7 +84,7 @@ $string['welcomep10'] = '{$a->installername} ({$a->installerversion})';
 $string['welcomep20'] = 'Βλέπετε αυτή τη σελίδα γιατί εγκαταστήσατε και ξεκινήσατε με επιτυχία το πακέτο <strong>{$a->packname} {$a->packversion}</strong> στον υπολογιστή σας. Συγχαρητήρια!';
 $string['welcomep30'] = 'Αυτή η έκδοση/διανομή <strong>{$a->installername}</strong> περιλαμβάνει τις εφαρμογές για τη δημιουργία ενός περιβάλλοντος μέσα στο οποίο θα λειτουργεί το <strong>Moodle</strong>, ονομαστικά:';
 $string['welcomep40'] = 'Το πακέτο περιλαμβάνει επίσης το <strong>Moodle {$a->moodlerelease} ({$a->moodleversion})</strong>.';
-$string['welcomep50'] = 'Η χρήση όλων των εφαρμογών σε αυτό το πακέτο υπόκειται στις αντίστοιχες άδειες. Ολόκληρο το πακέτο <strong>{$a->installername}</strong> είναι <a href="https://www.opensource.org/docs/definition_plain.html">λογισμικό ανοικτού κώδικα</a> και διανέμεται με την <a href="https://www.gnu.org/copyleft/gpl.html">GPL</a> άδεια.';
+$string['welcomep50'] = 'Η χρήση όλων των εφαρμογών σε αυτό το πακέτο υπόκειται στις αντίστοιχες άδειες χρήσης. Ολόκληρο το πακέτο <strong>{$a->installername}</strong> είναι <a href="https://www.opensource.org/docs/definition_plain.html">λογισμικό ανοικτού κώδικα</a> και διανέμεται με την άδεια χρήσης <a href="https://www.gnu.org/copyleft/gpl.html">GPL</a>.';
 $string['welcomep60'] = 'Οι παρακάτω σελίδες θα σας καθοδηγήσουν με εύκολα βήματα στην εγκατάσταση και ρύθμιση του <strong>Moodle</strong> στον υπολογιστή σας. Μπορείτε να δεχθείτε τις προεπιλεγμένες ρυθμίσεις ή προαιρετικά, να τις τροποποιήσετε ανάλογα με τις ανάγκες σας.';
 $string['welcomep70'] = 'Πατήστε το κουμπί «Συνέχεια» για να συνεχίσετε με την εγκατάσταση του <strong>Moodle</strong>.';
 $string['wwwroot'] = 'Διεύθυνση ιστού';
diff --git a/install/lang/ky/admin.php b/install/lang/ky/admin.php
index 8b6b7110a11..674950e97d4 100644
--- a/install/lang/ky/admin.php
+++ b/install/lang/ky/admin.php
@@ -41,3 +41,4 @@ $string['cliunknowoption'] = 'Таанылбаган параметрлер {$a}
 $string['cliyesnoprompt'] = 'У киргизиңиз (Ооба дегенди билдирет) же n киргизиңиз (Жок дегенди билдирет)';
 $string['environmentrequireinstall'] = 'Орнотуу жана күйгүзүү зарыл';
 $string['environmentrequireversion'] = '{$a->needed} версиясы талап кылынат, сиз колдонгон версия {$a->current}';
+$string['upgradekeyset'] = 'Жаӊыртуу ачкычы (аны көрсөткүӊүз келбесе бош калтырыӊыз)';
diff --git a/install/lang/ky/moodle.php b/install/lang/ky/moodle.php
new file mode 100644
index 00000000000..da1ac4b4f31
--- /dev/null
+++ b/install/lang/ky/moodle.php
@@ -0,0 +1,36 @@
+<?php
+// This file is part of Moodle - https://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <https://www.gnu.org/licenses/>.
+
+/**
+ * Automatically generated strings for Moodle installer
+ *
+ * Do not edit this file manually! It contains just a subset of strings
+ * needed during the very first steps of installation. This file was
+ * generated automatically by export-installer.php (which is part of AMOS
+ * {@link http://docs.moodle.org/dev/Languages/AMOS}) using the
+ * list of strings defined in /install/stringnames.txt.
+ *
+ * @package   installer
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+$string['language'] = 'Тил';
+$string['moodlelogo'] = 'Moodle логотиби';
+$string['next'] = 'Мындан ары';
+$string['previous'] = 'Артка';
+$string['reload'] = 'Жаңыртуу';
diff --git a/question/type/essay/tests/helper.php b/question/type/essay/tests/helper.php
index f1590a39909..48ba2b04e00 100644
--- a/question/type/essay/tests/helper.php
+++ b/question/type/essay/tests/helper.php
@@ -92,7 +92,7 @@ class qtype_essay_test_helper extends question_test_helper {
         $fromform->attachments = 0;
         $fromform->attachmentsrequired = 0;
         $fromform->maxbytes = 0;
-        $fromform->filetypeslist = '';
+        $fromform->filetypeslist = ''; // Although once saved in the DB, this becomes null, the form returns '' here.
         $fromform->graderinfo = array('text' => '', 'format' => FORMAT_HTML);
         $fromform->responsetemplate = array('text' => '', 'format' => FORMAT_HTML);

@@ -144,7 +144,7 @@ class qtype_essay_test_helper extends question_test_helper {
         $fromform->attachments = 3;
         $fromform->attachmentsrequired = 0;
         $fromform->maxbytes = 0;
-        $fromform->filetypeslist = '';
+        $fromform->filetypeslist = ''; // Although once saved in the DB, this becomes null, the form returns '' here.
         $fromform->graderinfo = array('text' => '', 'format' => FORMAT_HTML);
         $fromform->responsetemplate = array('text' => '', 'format' => FORMAT_HTML);

@@ -181,7 +181,7 @@ class qtype_essay_test_helper extends question_test_helper {
         $fromform->attachments = 0;
         $fromform->attachmentsrequired = 0;
         $fromform->maxbytes = 0;
-        $fromform->filetypeslist = '';
+        $fromform->filetypeslist = ''; // Although once saved in the DB, this becomes null, the form returns '' here.
         $fromform->graderinfo = array('text' => '', 'format' => FORMAT_HTML);
         $fromform->responsetemplate = array('text' => '', 'format' => FORMAT_HTML);

diff --git a/version.php b/version.php
index 55fa04920d5..0a84f5f855f 100644
--- a/version.php
+++ b/version.php
@@ -29,9 +29,9 @@

 defined('MOODLE_INTERNAL') || die();

-$version  = x;              // x      = branching date YYYYMMDD - do not modify!
+$version  = x;              // YYYYMMDD      = weekly release date of this DEV branch.
                                         //         RR    = release increments - 00 in DEV branches.
                                         //           .XX = incremental changes.
-$release  = '3.11dev (Build: x)';// Human-friendly version name
-$branch   = '311';                      // This version's branch.
+$release  = '4.0dev (Build: x)'; // Human-friendly version name
+$branch   = '400';                      // This version's branch.
 $maturity = MATURITY_ALPHA;             // This version's maturity level.