According a Microsoft documentation the deployment method for SSIS packages has changed starting with SSIS 2012.
The legacy model still exists for backward compatibility.
The new model is Project Deployment Model, the old is a Package Deployment Model.
In the new model Parameters are used to assign values to package properties.
In the old model Configurations files are used to assign values to package properties.
My question is, in the future will you be converting to the new model? If so when?