I have an app on my headless RPi which runs from boot via a systemd service file with StandardInput=tty. It has been running like this for 18 months and I have updated my system very frequently. However, since the kernel update:
2018-02-13 07:02 linux-raspberrypi 4.9.80-1 -> 4.14.18-1
The console input is not attaching to the app. I downgraded the kernel back to 4.9.80-1 (and a few others before that) where it works. I recreated the same issue and downgraded to fix on another RPi also.