Final answer:
A limitation of the Field Service mobile app is that Windows 10 phones do not support it, you cannot work offline, and you cannot create follow-ups.
Step-by-step explanation:
A limitation of the Field Service mobile app is that Windows 10 phones do not support the app. This means that if a user has a Windows 10 phone, they will not be able to use the app. Additionally, you cannot work offline using the app, so a stable internet connection is required for its functionality. Another limitation is that you cannot create follow-ups within the app, which may limit some workflow capabilities.