The Portal’s Auto Upgrades will only work with Endpoint that were built on the Portal or upgraded manually from the clupgrade.exe file built on the Portal with Enable Automatic Software Updates set to YES, and Update from Portal selected.

The Portal was released with RBackup version 11.9.0. So, it will not upgrade previous versions of the RBackup Endpoint. However, it can upgrade Endpoints whose installers were built on the Portal with the above options selected, or who were upgraded manually the first time using the clupgrade.exe file created on the Portal with the above options selected. 

So, manually upgrade your existing Endpoints one time using the clupgrade.exe that you create on the Portal, and use the Portal to build and install all future Endpoint software, and then you can use it to push out upgrades from the Portal.