Please list the conditions that make a dfu_application.zip be marked as invalid in the device manager android api ?

Hello

Can you please list the conditions that make a dfu_application.zip be marked as invalid in the device manager ?

Because that's what I get recently (was not the case before)

App v 1.7.0  unchanged

I am using nrfconnect sdk v2.1.0 unchanged

what changed is my .conf, code and vscode version

It  prevents me from trying to fw upgrade in advanced mode.