OpenSSL 4.1 was released on October 23, 2026, introducing support for the DTLS 1.3 protocol and the GREASE mechanism. The update enhances performance for post-quantum cryptographic algorithms, specifically optimizing ML-DSA and ML-KEM operations for various processor architectures.
The release includes performance improvements for x86-64 processors with AVX-512 instruction set support, focusing on SHAKE x4 operations for ML-DSA and AES-CBC decryption. Additionally, the library now provides initial support for the Elbrus 2000 (E2K) architecture and adds IKEv2 key derivation function support.
Maintenance changes include the removal of build support for Windows CE and Windows Itanium platforms. The project also deleted the 'no-ecdsa' and 'no-ecdh' configuration options, directing users to use 'no-ec' instead. The 'tsget' tool has been updated to use the Net::Curl::Easy Perl module.
Developers are advised to review the release notes regarding known issues with DTLS 1.3, such as potential handshake problems under specific packet loss conditions. Organizations should validate these features in test environments before deploying the update to critical production systems.
