Version 21.0.x introduced better native handling of "jitter" and "packet loss" sensors for VoIP quality monitoring—critical as hospitals migrated to softphones during the pandemic recovery period of 2021-2022.
If you are currently running version 21.0.x, planning a migration to it, or trying to understand its legacy in the shadow of newer releases, this article covers everything you need to know. prtg network monitor 21.0.x
SNMP monitoring was refined extensively: Version 21
The initial login and password are set to prtgadmin / prtgadmin . planning a migration to it
Mastering PRTG Network Monitor 21.0.x: Stability, Security, and Speed