Can't update drupalchat schema

I get the following on social distro with drupal 8.3.7:

Argument 4 passed to db_add_index() must be of the type array, none given, called in [error]
social-8.x-1.6-drupal-8.3.7/html/modules/contrib/drupalchat/drupalchat.install
on line 133 and defined database.inc:929
Argument 4 passed to Drupal\Core\Database\Driver\mysql\Schema::addIndex() must be of the type array, [error]
null given, called in
social-8.x-1.6-drupal-8.3.7/html/core/includes/database.inc
on line 930 and defined Schema.php:510
MySQL needs the 'uid1' field specification in order to normalize the 'uid1' index [error]
Performing drupalchat_update_8000 [ok]
Failed: MySQL needs the 'uid1' field specification in order to normalize the 'uid1' index [error]