funknetz/docs/adr/0006-configured-protocol.md

# The config chooses the protocol; the other is one fallback session

The station announces the protocol named in the config. The default is v2. It opens one session of the other protocol only when the reflector refuses the configured version and names the other as acceptable: a downgrade or an “at most 2.x” error when v3 was announced, and a downgrade to 3.0 or a “must be at least 3.0” error when v2 was announced. The connection after that session announces the configured protocol again. A TLS, CA, or hostname failure retries the configured protocol and does not switch, so a certificate problem does not become a plaintext session. Always announcing 3.0 was rejected because the operator has to be able to stay on v2.
	`# The config chooses the protocol; the other is one fallback session`

	The station announces the protocol named in the config. The default is v2. It opens one session of the other protocol only when the reflector refuses the configured version and names the other as acceptable: a downgrade or an “at most 2.x” error when v3 was announced, and a downgrade to 3.0 or a “must be at least 3.0” error when v2 was announced. The connection after that session announces the configured protocol again. A TLS, CA, or hostname failure retries the configured protocol and does not switch, so a certificate problem does not become a plaintext session. Always announcing 3.0 was rejected because the operator has to be able to stay on v2.