Through the new_terms rule type, this rule detects potential HTTP downgrade attacks by identifying HTTP traffic that uses a different HTTP version than the one typically used in the environment. An HTTP downgrade attack occurs when an attacker forces a connection via an older HTTP version, resulting in potentially less secure communication. For example, an attacker might downgrade a connection from HTTP/2 to HTTP/1.1 or HTTP/1.0 to exploit known vulnerabilities or weaknesses in the older protocol versions.