Compiler message "L9931W: Your license for feature compiler5 will expire in 15 days"

Not really, same issue were discussed few days ago in the context of Mbed Studio -

Yeas that is right and it is because only Keil Studio still is developing. Mbed Studio will be replaced with Keil Studio desktop maybe in the future after Keil Studio Cloud achive its final face, probably.

BR, Jan