The "offline" moniker is deceptive. Many versions of KMSpico collect telemetry. Since the code is proprietary and obfuscated, no one knows exactly what data is being sent. It could harvest your browsing history, saved passwords, or even private keys for cryptocurrency wallets.
According to release notes circulating on activation forums, KMSpico v41 supports the following: kmspico v41 offline office and windows activator