When a service is changed, which properly happened in the update, the command systemctl daemon-reload needs to be run. The warning just tells you it hasn’t happened, and the old version is being used.
This is unlikely to result in your system rebooting.
Try booting an old kernel, if your system can’t boot after an update it’s often related to the kernel.
At the blue boot screen, you can use the advanced menu option to select older kernels.