This is a patch release containing the fix: "Use a full-length key even with null ciphers" This was both a compatibility and security issue, full details are available at https://github.com/cisco/libsrtp/pull/559 . The following links are available for downloading: https://github.com/cisco/libsrtp/archive/v2.4.1.tar.gz https://github.com/cisco/libsrtp/archive/v2.4.tar.gz https://github.com/cisco/libsrtp/archive/v2.tar.gz Thank you. libSRTP team.