The Pure Storage Plug-In for Veeam Backup & Replication has been updated to version 1.3.18. This is a maintenance release and the rather brief KB is KB4129.
Find the latest version by visiting the Veeam Backup & Replication Download page, scrolling down to the Storage Plug-Ins section, and clicking Pure Storage Plug-In for Veeam Backup & Replication.
You can check which version you currently have installed by opening Apps & Features on the Windows Server hosting your Veeam Backup and Replication Server. The previous version is 1.2.45.
The upgrade process is to simply install the new version in place. It is not necessary to first uninstall the older version of the plug-in and a reboot of the VBR server is not required.