Sigma4pc is a site known for providing "pre-activated" or "cracked" versions of premium software. Using these files involves several dangers:
: Modified VPN clients can be designed to "eavesdrop" on your connection or route your traffic through malicious servers instead of protecting it.
Is my VPN connection secure and private? - Hotspot Shield Support
: These versions do not receive security patches or official updates from the developer, leaving you vulnerable to new exploits. Safe Ways to Use Hotspot Shield