booking new kernel (5.2) in old userland (5.1) to multiuser?

[Jev]

I need to do a remote installworld and I would like to see if anyone has 
had issues with booting (remotely or other) a new 5.2-RELEASE kernel and 
  friends in an old 5.1 userland?

Any issues with this? any extra precautions that can be taken? Serial 
console and such isn't an option.

Thanks,
-Emil