In T219135 we are migrating all mediawiki maintenance crons to PHP 7.2.
One of them is cron { 'tor_exit_node_update': which also runs on labweb1001/1002. Trying to convert it to PHP7.2 lead to failure and cron spam because labweb hosts don't have PHP 7.2.
Cron Daemon <root@labweb1001.wikimedia.org> 7:00 AM (3 hours ago) to www-data /usr/local/bin/mwscript: line 25: php7.2: command not found
They will need to be upgraded. This means Wikitech needs to move to it.