device name/path disappeared/changed after upgrade

Hello,

we have a server with a physical raid (for a long time) whose partitions where exposed and mounted in fstab like /dev/sda2 and /dev/sda4.

Yesterday we upgraded from openSuse 15.1 to 15.2 and thus a major kernel update to (5.3.18-lp152.72-default)

The machine did not come up because it was unable to find and mount it'S partitions - seems the /dev/sda4 was gone.

we changes fstab to use UUIDs to mount the devices and it worked.

looking in yast partitioner I see the device is now
/dev/mapper/3600605b006ac36601874f0590b0b6a5b-part4

Code:# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 5,5T 0 disk
sda1 8:1 0 10G 0 part
sda2 8:2 0 512M 0 part
sda3 8:3 0 60G 0 part
sda4 8:4 0 5,4T 0 part
sda5 8:5 0 1M 0 part
3600605b006ac36601874f0590b0b6a5b 254:0 0 5,5T 0 mpath
3600605b006ac36601874f0590b0b6a5b-part1 254:1 0 10G 0 part [SWAP]
3600605b006ac36601874f0590b0b6a5b-part2 254:2 0 512M 0 part /boot
3600605b006ac36601874f0590b0b6a5b-part3 254:3 0 60G 0 part /
3600605b006ac36601874f0590b0b6a5b-part4 254:4 0 5,4T 0 part /srv/data
3600605b006ac36601874f0590b0b6a5b-part5 254:5 0 1M 0 partso lsblk still shows /dev/sda4, but it looks like a completely different thing now.

note: we have no LVM used or configured. ("lvs" returns nothing)

so we wonder: what happened!!!???

is this a change in the kernel ? in the handling of physical RAIDs ? a new security feature ?

Cheers Tom.