I know it's rather a question to Keil but maybe someone came across this issue.
The uVision cannot find STM32L496ZGTxP MCU when the IDE starts. The current DFP is 2.0.0 (2017-10-06).
I ignored the warning and successfully compiled simple program.
It seems I have no access to peripherals during debugging session.
The project skeleton was generated using CubeMX 4.25.0
Keil uVision 5.25. I have not found never Device Pack than 2.0.0