Historically, Sophos relied on a customized version of OpenVPN for SSL connections. However, the Sophos Connect client utilizes a proprietary implementation that communicates over TCP port 443 or UDP port 443.
The file is the standard Windows installer for Sophos Connect 2.5, a "platform release" designed primarily to add support for ARM64 Windows devices while maintaining support for x64 systems. Key Technical Profile Version: 2.5.0.146 (GA release). Protocols: Supports both IPsec and SSL VPN remote access. sophosconnect_2.5.0_ga_ipsec_and_sslvpn.msi