Hi @mautz,
Once you have a little time you may want to switch these on in your kernel (cm13):

# CONFIG_UTS_NS is not set
# CONFIG_USER_NS is not set
# CONFIG_PID_NS is not set

These are required for Flatpak, if somebody would like to play with that on this rom.

The rest of the flags are already on.
CONFIG_IPC_NS=y
CONFIG_NET_NS=y
CONFIG_NF_CONNTRACK_NETBIOS_NS=y

(Most of them are off in my cm12.1 kernel, so I'll go a re-compile. )