diff --git a/core/modules/datetime_range/datetime_range.install b/core/modules/datetime_range/datetime_range.install
new file mode 100644
index 0000000..6767526
--- /dev/null
+++ b/core/modules/datetime_range/datetime_range.install
@@ -0,0 +1,41 @@
+<?php
+
+/**
+ * @file
+ * Install, update and uninstall functions for the Datetime range module.
+ */
+
+/**
+ * Allow NULL in the field end_value column.
+ */
+function datetime_range_update_8600() {
+  $field_storage_configs = \Drupal::entityTypeManager()
+    ->getStorage('field_storage_config')
+    ->loadByProperties(array('type' => 'daterange'));
+
+  foreach ($field_storage_configs as $config) {
+    $entity_type = \Drupal::entityTypeManager()
+      ->getDefinition($config->getTargetEntityTypeId());
+    $table_mapping = \Drupal::entityTypeManager()
+      ->getStorage($config->getTargetEntityTypeId())
+      ->getTableMapping();
+
+    // Prepare the list of field tables to alter, taking into account if the
+    // entity type is revisionable.
+    $tables = [$table_mapping->getDedicatedDataTableName($config)];
+    if ($entity_type->isRevisionable()) {
+      $tables[] = $table_mapping->getDedicatedRevisionTableName($config);
+    }
+
+    // The 'not null' default value is FALSE, but it's set explicitly to avoid
+    // any confusion.
+    $schema = $config->getSchema();
+    $schema['columns']['end_value']['not null'] = FALSE;
+
+    $field_name = $config->getName() . '_end_value';
+    foreach ($tables as $table) {
+      \Drupal::database()->schema()
+        ->changeField($table, $field_name, $field_name, $schema['columns']['end_value']);
+    }
+  }
+}