The 5.5.1 version floating around the internet is a designed to work with cheaper clone cables (usually the blue "VAG CAN Pro" USB dongles found on eBay or AliExpress for $30 instead of $300).

VAG CAN PRO (VCP) 5.5.1 software is a specialized diagnostic and programming tool for Volkswagen, Audi, Seat, and Skoda vehicles, primarily those manufactured between 1990 and 2015. It is favored by advanced users for tasks that more common tools, like VCDS, cannot always handle, such as deep-level module flashing and EEPROM editing. Key Features of VCP 5.5.1 One-Click Functions (OCLF):

Vag Can Pro (VCP) is a professional-grade diagnostic interface protocol that allows deep-level access to VAG vehicle systems. Version 5.5.1, released several years ago, offered:

Simplifies adding new equipment (like retrofitting LED headlights) by automatically calculating and applying necessary vehicle coding. Protocol Support: Compatible with protocols. Implementation & Setup VCP VAG CAN PRO V5.5.1 Professional Diagnostic ... - VXDAS

Supports ESP MK60EC1 decision coding blocks and PR-codes for easier controller configuration. AliExpress Login Finder: Scans and retrieves login codes for UDS controllers. Compatibility and Requirements

VCP is a professional-grade diagnostic system designed specifically for VAG vehicles (VW, Audi, Seat, Skoda). Version 5.5.1 is a popular "stable" iteration often used by DIY enthusiasts for advanced modifications. Key Features