[dan@besser:/usr/local/www/librenms] $ sudo ./validate.php

In Application.php line 670:

  Class 'Illuminate\Notifications\NexmoChannelServiceProvider' not found


====================================
Component | Version
--------- | -------
LibreNMS  | 1.55
DB Schema | Not Connected (0)
PHP       | 7.2.22
MySQL     | ?
RRDTool   | 1.7.2
SNMP      | NET-SNMP 5.7.3
====================================

[OK]    Installed from package; no Composer required
[dan@besser:/usr/local/www/librenms] $