I have downloaded EU A08 update and extracted the kernel. I have also patched it with Magisk app. I will attach both in case it will help someone.
EDIT:
I have successfully updated from A07 to A08 while keeping root. Here are the steps I have taken:
1. Unroot with Magisk app (restore images)
2. Reboot
3. Install update (phone should reboot)
4. Make sure update is installed in Settings > About > Version
5. adb reboot bootloader
6. Boot patched image attached here (unzip first)
7. Use Magisk to Direct Install
8. Reboot
9. ????
10. Profit
Also
@MNoisy both the A07 and A08 kernels have the same build numbers, the A08 stock image I posted here might work for you in some manner. I was able to boot A08 kernel on A07 system.