diff --git a/admin/tool/analytics/model.php b/admin/tool/analytics/model.php
index 6b7511b16d8..ab9f304143a 100644
--- a/admin/tool/analytics/model.php
+++ b/admin/tool/analytics/model.php
@@ -159,6 +159,10 @@ switch ($action) {
                 $predictionsprocessor = false;
             }
 
+            if (!isset($data->contexts)) {
+                $data->contexts = null;
+            }
+
             $model->update($data->enabled, $indicators, $timesplitting, $predictionsprocessor, $data->contexts);
             redirect($returnurl);
         }
diff --git a/analytics/classes/model.php b/analytics/classes/model.php
index cc92516b297..9e484b10420 100644
--- a/analytics/classes/model.php
+++ b/analytics/classes/model.php
@@ -493,13 +493,15 @@ class model {
             $predictionsprocessor = $this->model->predictionsprocessor;
         }
 
-        if ($contextids !== false) {
+        if ($contextids === false) {
+            $contextsstr = $this->model->contextids;
+        } else if (!$contextids) {
+            $contextsstr = null;
+        } else {
             $contextsstr = json_encode($contextids);
 
             // Reset the internal cache.
             $this->contexts = null;
-        } else {
-            $contextsstr = $this->model->contextids;
         }
 
         if ($this->model->timesplitting !== $timesplittingid ||
diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index aac3464c46a..ee6b58ad9a9 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -3754,5 +3754,14 @@ function xmldb_main_upgrade($oldversion) {
         upgrade_main_savepoint(true, 2019102500.04);
     }
 
+    if ($oldversion < 2019103000.13) {
+
+        $DB->execute("UPDATE {analytics_models} set contextids = null
+                       WHERE contextids = :zero or contextids = :null", ['zero' => '0', 'null' => 'null']);
+
+        // Main savepoint reached.
+        upgrade_main_savepoint(true, 2019103000.13);
+    }
+
     return true;
 }
diff --git a/version.php b/version.php
index 7293cec9984..a310d959521 100644
--- a/version.php
+++ b/version.php
@@ -29,7 +29,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$version  = 2019103000.00;              // YYYYMMDD      = weekly release date of this DEV branch.
+$version  = 2019103000.13;              // YYYYMMDD      = weekly release date of this DEV branch.
                                         //         RR    = release increments - 00 in DEV branches.
                                         //           .XX = incremental changes.