Why am I getting this message: Saving these changes will deactivate the Mobile Builder for this App?

In addition to the Mobile Builder, GoCanvas also offers the Advanced App Builder and PDF Designer. There are a number of features that are only available from the Advanced App Builder, like Reference Data and conditional logic, as well as further customizations you can make in the PDF Designer. 

Making changes to your App from the Advanced App Builder or the PDF Designer will automatically disable the Mobile Builder for that specific App. 

You will still be able to use the Mobile Builder for other Apps on your account.

Additional features, like Workflow and Dispatch, are also only accessibly from the GoCanvas website and will disable the Mobile Builder when enabled.