As you know, Veeam released the service pack 4 on January 2019, it’s not fix bugs only, it also includes a lot of new features –
Support for Microsoft Windows Server 2019,
Application-level monitoring,
Dedicated view for job and disk-based alarms, Veeam Agents support, Enhanced Cloud Gateway view, Enhanced “Cloud Connect Inventory” report, Microsoft Hyper-V 2019 Support…
The details information you can check from Veeam website https://www.veeam.com/veeam_one_9_5_whats_new_wn.pdf and https://www.veeam.com/veeam_one_9_5_u4_release_notes_rn.pdf.
The steps are straightforward, but you still need to be careful about one thing, the first one is “If you use Veeam ONE to monitor Veeam Backup & Replication or Veeam Cloud Connect, be sure to install Update 4 for Veeam ONE 9.5 first” and the second is “If you are a tenant of a cloud provider, please contact your provider before upgrading to ensure the provider has applied Update 4 on their end”.