B. Diddy thinks correct - UFS 3.0 is being used for
internal storage. The external storage is still SD. But ... UFS 3.0 isn't a new
file system, it's new
hardware. The file system is still ext3. (And the file system on the SD card is still FAT32 or exFAT, depending on the card's size but, as @
svtcobra points out,, if you encrypted it in the old phone, decrypt it
in the old phone first, then put it into the new phone and encrypt it. Part of the encryption key is part of the hardware of the phone.)