There is one critical update in Sprint '17 release, which is Enable Lightning LockerService Security. How will this affect lightning components? We currently don't use lightning components except Process builder in our project. So is it going to affect Process builder functionality as well?
Locker service only applies to custom components currently - standard components/applications run in system mode and are not impacted by the LS rollout.
Here you can find all the documentation about the impact on your lightning components:
E.g.: Standard markup like
<input> will crash if you do not replace it with
I have not read anything about
Process Builder impact (yet).