This guide provides information on the IGC Season18 lightweight client, which is compatible with all IGC versions. Instructions: 1) Ensure vcredist is installed; the official Microsoft download link is https://aka.ms/vs/17/release/vc_redist.x64.exe. 2) Locate the ./IGC.dll and ./Data/Local/serverlist.bmd files in the IGC client; copy them to the directory of the lightweight client at ./Data/IGC. Edit the ./Data/Partition.inf file with accurate game details, including name, IP address, and port. 3) Capture the login packet of main.exe using a packet capture tool. Open DecIGC-Login.exe, paste the encrypted login packet for decryption in the format C3 73 XX..., and copy the decrypted version number and verification code to the file ./Data/cVersion under the lightweight client directory. 4) With these steps completed, you can now log in to the game effortlessly.