File setuid/setgid bits not restored: urbackupclientcli

is it expected that setuid/setgid are not restored by the linux client urbackupclientctl ?
Though the sticky bit is restored properly.
When I backup a 7777 mode file, restore-start gives 1777 as file mode.

zip from server does not restore any file ownership/attributes. Is there another mode of web retrieval (tar) ?

server is 2.1.19 on an iomega ix2-cloud (armv5soft entware-ng package): LIfeline OS now Lenovo (debian based)
linux cli client (x86_64) 2.1.16 is: a debian unstable desktop.