One-window patching. Drop RF_Online.bin or its folder on the window, or browse to it, and press Patch client; it replaces the clientpatcher.ps1 script, so no PowerShell is needed.
Build recognition. It names RF Online 4.55, 4.15 (RedFox), 2.1.6, 1.5 (GamesCampus), V105 and V108 and switches on the fixes that build needs; any other file is refused and left untouched.
Patch details. Each fix explains the check it removes and lists every offset in the file with the bytes before and after.
Backups and restore. Every write leaves a dated backup beside the client, and Restore original puts back every byte as the build shipped.
Window mode. On a client that reads it from R3Engine.ini, it sets windowed or full screen, and uses your desktop's resolution for full screen when your display cannot run the one in the file.
Monster aura repair on RF Online 1.5. It repairs the monster aura list that leaves about 200 monsters without their glow.
Administrator retry. When Windows will not let it write beside the client, it offers Run as administrator.
Self-updates. It downloads a newer signed version in the background and installs it the next time it starts.