Had some problems where the Sonar Poller Stopped working. Think some packages got removed so trying to run
sudo php /opt/poller/bin/checkForUpgrades.php
Returned a php error that it was not installed. Installed it with all the other dependencies to fix the problem.
Note that php version is different then it is on the github page. php7.2-cli is installed instead of php7.0-cli.
sudo apt-get install php7.2-cli php-zip php-snmp php-sqlite3 php-bcmath php-mbstring php-dom git fping snmp redis-server monit ntp snmp-mibs-downloader