Midfp (Message-ID Fingerprinter) determines the mail client from the message-id which is included in an email. It analyzes the structure of the message-id and compares it with regular expressions against a database.
You can download it from the following link: https://packetstormsecurity.com/files/download/81301/midfp-1.0.tar.gz
Source: https://packetstormsecurity.com/files/81301/Message-ID-Fingerprinting-Tool.html