Comment # 2 on bug 909307 from Marius Tomaschewski

OK, the fix is in git master now and will be in wicked-0.6.16 release,
(wicked + sysconfig which provides the variables) test RPMs are at:

http://download.opensuse.org/repositories/network:/wicked:/master/SLE-12_GA/

Please test and let us know if this works for you.

See "man 5 ifcfg-dhcp", the variables DHCLIENT_USER_CLASS_ID and
DHCLIENT_USER_CLASS_FORMAT (there is some confusion about the
option: while there is RFC3004 which defines its format, dhcp
servers often/usually can't deal with it but expect a string,
[not the rfc array of len + id-string tuples].