HHVM 4.172.0 and all prior versions use TLS 1.0 for secure connections when handling tls:// URLs in the stream extension. TLS1.0 has numerous published vulnerabilities and is deprecated. HHVM 4.153.4, 4.168.2, 4.169.2, 4.170.2, 4.171.1, 4.172.1, 4.173.0 replaces TLS1.0 with TLS1.3. Applications that call stream_socket_server or stream_socket_client functions with a URL starting with tls:// are affected.
https://hhvm.com/blog/2023/01/20/security-update.html
https://github.com/facebook/hhvm/commit/083f5ffdee661f61512909d16f9a5b98cff3cf0b