The main reason for the change is the charging station. This envelope can be - definitely - load with the original Sony Ladestaion the Z1, without having to remove the shell. The recess on the relevant side with the magnetic contacts is very large and with the greater use I could yesterday load the Z1 first time in the protective sheath.
For "dangerous" excursions, about the swimming pool with smooth tiles and slipping, but I would change the envelope well. My confidence in the protection is limited. For 1 star deduction that. 4 stars for lasting beauty, fit and that it is to my knowledge the only shell that can use in the charging station