The OpenSSL Library now supports Encrypted Client Hello (ECH)

Previous posts about the upcoming OpenSSL 4.0 release:

1. removing ENGINE code
2. removing deprecated functions for creating or modifying custom METHODS
3. no longer registering a function via atexit function

Summary

The OpenSSL Library now supports Encrypted Client Hello (ECH)
specified in RFC 9849,
which was published this month. Applications that implement this
standard will be able to encrypt sensitive information that is
currently transmitted in plaintext in the TLS 1.3 handshake. In
particular, ECH can protect the client’s target server name from being
revealed to third parties.