We had to postpone Salesforce files usage to the future, as just found out that Classic app for Android/iPhone does not have SF files support.
Half of business is using FSA tablet app and half of is using Classic mobile app. As SF files is org wide setting, there is no way to handle this situation.
According to your Support new ServiceMax Go app is not supporting SF files either. Both businesses are really waiting for this new mobile app and SF files support is needed.
Salesforce Files support was added for FSA in 19.1.
We will be adding Salesforce Files support to ServiceMax Go in the upcoming 1.2 release. Customer Org must be 19.1 or higher in order to use Salesforce Files with ServiceMax Go.