Which Windows version was the first to support the SMB2 protocol?

Windows Vista was the first Windows version to support the SMB2 protocol. Microsoft introduced SMB 2.0 with Windows Vista and its server counterpart, Windows Server 2008, as a major redesign of the older Server Message Block networking protocol.

SMB2 reduced network overhead by allowing multiple commands to be sent in a single packet and increased the size and number of operations that could be handled efficiently. It also added features such as durable handles and improved support for symbolic links. These changes made file sharing more suitable for modern, higher-latency networks.

Windows Vista remained backward-compatible with SMB1, so it could communicate with older systems running Windows 2000, Windows XP, or Windows Server 2003. During connection setup, the client and server negotiated a common protocol; if either side lacked SMB2 support, the connection fell back to SMB1. Windows 7 later introduced SMB 2.1, not the original SMB2 release.