The majority of Muslims in the world are not following Quran rather do all that opposite what Quran commands them Don't do. The present Muslims prefer to follow those fake Hadees invented by Persian writers. Mirza Ghulam Ahmed of Quadyaan took the advantage of those fake Hadees and declared himself as Prophet. There is nothing mentioned in Quran that a new prophet will come with a new message.
According to (Late) Sheikh Ahmed Deedat all those previous Prophets came with some messages from Allah (SWT) and Holy Prophet Mohammad (S) brought complete messages in form of Quran covering all life pertaining issues from Zero to 9. There is nothing left behind.
If we accept Mirza Sahib as Prophet we want to know what new message he brought for mankind.
The answer is all big Zero.