Sometimes we need to update some settings for a field. In our case we will be update drop down field
function your_module_update_8001() {
// First we need to get update manager.
$definition_update_manager = \Drupal::entityDefinitionUpdateManager();
// Load the storage definition of the field.
$field_storage = $definition_update_manager->getFieldStorageDefinition('field_name',
'node');
// Set a new list of options for the list field.
$field_storage->setSettings([
'allowed_values' => [
'link' => 'Link',
'posts' => 'Posts',
'events' => 'Events',
'page' => 'Page',
],
]);
// Update the field storage definition.
$definition_update_manager->updateFieldStorageDefinition($field_storage);
}