An application is a collection of devices with the same purpose / of the same type. Think of a weather station collecting data at different locations for example.
When creating an Application, you need to select the Service Profile which will be used for the devices created under this Application. Note that once a Service Profile has been selected, it can't be changed.
The payload codec options have moved to the Device Profile. For backward compatibility, existing codec configuration on the application is still accessible and functional, but this will be removed fully in the next major release update.
For documentation on the available integrations, please refer to Sending and Receiving.
Multiple Devices can be added to the Application.