I wrote a post on What’s new in application requests in Configuration Manager 1906 over at 4sysops.com https://4sysops.com/archives/whats-new-in-application-requests-in-sccm-1906/ One of the things that is new i the possibility to Retry an Installation if it fails or is uninstalled manually for example. In the post over at 4Sysops I had three sample scripts on how to