Just had a migration where I was blocked by not having the msdyn_FSMNotifications solution installed in my target environment.

The secret behind it: this solution can only be installed on top of Woodford.

So after you have installed Woodford you’ll need to go to the Instance Picker and click on Install (or Upgrade if available) for Field Service, even if it is already installed. This way only some additional solutions will be installed. There you go!

Sources / more information:
https://docs.microsoft.com/en-us/dynamics365/field-service/upgrade-field-service
https://docs.microsoft.com/en-us/dynamics365/field-service/mobile-push-notifications