curl/docs/cmdline-opts/http2.md

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c: Copyright (C) Daniel Stenberg, daniel@haxx.se, et al. SPDX-License-Identifier: curl Long: http2 Tags: Versions Protocols: HTTP Added: 7.33.0 Mutexed: http1.1 http1.0 http2-prior-knowledge http3 Requires: HTTP/2 Help: Use HTTP/2 Category: http Multi: mutex See-also:

• http1.1
• http3
• no-alpn Example:
• --http2 $URL ---

--http2

Use HTTP/2.

For HTTPS, this means curl negotiates HTTP/2 in the TLS handshake. curl does this by default.

For HTTP, this means curl attempts to upgrade the request to HTTP/2 using the Upgrade: request header.

When curl uses HTTP/2 over HTTPS, it does not itself insist on TLS 1.2 or higher even though that is required by the specification. A user can add this version requirement with --tlsv1.2.