To use the tool effectively with the v1.7 patch, follow these general steps: Preparation

Open Call of Duty 4: Modern Warfare and go to the Multiplayer menu.

: Click the "Easy Upgrade" or "Level 55" button while the game is running (some versions require the game to be at the multiplayer menu). Refresh Profile

The official master server is offline. Use a community client like COD4x (which upgrades v1.7 to v1.8+) or manually connect via IP.