According to both Islam and the New Message from God, Muhammad was the last Messenger of God. Baha'i's believe that Muhammad was the penultimate Messenger. Most Christians do not recognize Muhammad as a prophet at all.
According to the New Message from God, Muhammad was the last Messenger of God. The New Message says that the Seal of the Prophets has been opened, bringing the current Messenger of God, Marshall Vian Summers.