I guess v6 requires 1.4.2 - are the devices staying connected long enough to pull in the new application and the device OS update?
Could it be that users somehow interfere with the device update process?
@volker Best not to share in a screen shot the device IDs.
If you look at kitty_aardvark device in the console and click on Edit button do you have the device Locked or Unlocked for updates? Toggling the Lock/Unlock with Flash Now ticked will get the device updating immediately if that is what you want to.
Update - I have a remote command on all devices to complete what they are doing and then reset, I have found that since the Forced OTA feature in 1.2.1 this hasn’t been necessary to use.