o Removed the heartbeat message in DTLS feature.
o Added EVP_KDF, an EVP layer KDF API, and a generic EVP_PKEY to EVP_KDF
bridge.
+ o All of the low level MD2, MD4, MD5, MDC2, RIPEMD160, SHA1, SHA224,
+ SHA256, SHA384, SHA512 and Whirlpool digest functions have been
+ deprecated.
Major changes between OpenSSL 1.1.1 and OpenSSL 1.1.1a [20 Nov 2018]