engor@engorx1:~/Downloads$ sudo dpkg -i linux-headers-4.13.0-041300rc6_4.13.0-041300rc6.201708201831_all.deb
(Reading database ... 281073 files and directories currently installed.)
Preparing to unpack linux-headers-4.13.0-041300rc6_4.13.0-041300rc6.201708201831_all.deb ...
Unpacking linux-headers-4.13.0-041300rc6 (4.13.0-041300rc6.201708201831) over (4.13.0-041300rc6.201708201831) ...
Setting up linux-headers-4.13.0-041300rc6 (4.13.0-041300rc6.201708201831) ...

engor@engorx1:~/Downloads$ sudo dpkg -i linux-headers-4.13.0-041300rc6-generic_4.13.0-041300rc6.201708201831_amd64.deb
(Reading database ... 281073 files and directories currently installed.)
Preparing to unpack linux-headers-4.13.0-041300rc6-generic_4.13.0-041300rc6.201708201831_amd64.deb ...
Unpacking linux-headers-4.13.0-041300rc6-generic (4.13.0-041300rc6.201708201831) over (4.13.0-041300rc6.201708201831) ...
Setting up linux-headers-4.13.0-041300rc6-generic (4.13.0-041300rc6.201708201831) ...
Examining /etc/kernel/header_postinst.d.
run-parts: executing /etc/kernel/header_postinst.d/dkms 4.13.0-041300rc6-generic /boot/vmlinuz-4.13.0-041300rc6-generic
ERROR (dkms apport): kernel package linux-headers-4.13.0-041300rc6-generic is not supported
Error! Bad return status for module build on kernel: 4.13.0-041300rc6-generic (x86_64)
Consult /var/lib/dkms/r8168/8.043.02/build/make.log for more information.

sudo apt purge r8168-dkms