* BACKWARDS INCOMPATIBLE: Support for Python 2.6 has been dropped. The last version of cryptography that supports Python 2.6 is 2.1.4.
* Resolved a bug in HKDF that incorrectly constrained output size.
* Added BrainpoolP256R1, BrainpoolP384R1, and BrainpoolP512R1 to support inter-operating with systems like German smart meters.
* Added token rotation support to Fernet with rotate().
* Fixed a memory leak in derive_private_key().
* Added support for AES key wrapping with padding via aes_key_wrap_with_padding() and aes_key_unwrap_with_padding() .
* Allow loading DSA keys with 224 bit q.
Thanks to everyone who contributed!
-Paul Kehrer (reaperhulk)