Hi @AkshatVyas,
We have an example implementation of an Update Module that uses DFU to update a leaf device. It is described in this article, source code is in the corresponding git repository.
The example uses a K64F-board, but it is easily adjusted to other device types. Concerning the type of software on the leaf device, it is completely agnostic as the update process is happening externally to it.
Greetz,
Josef