The focus of this release has been on stabilizing the existing functionality of 1.0.x, fixing bugs and providing a production ready DTLS implementation so that CoAP clients and servers can communicate securely with each other.
During the course of development, major parts of the protocol stack have been refactored or rewritten in order to make Californium suitable for production use cases. The test suite has been signifacantly extended to increase test coverage and assert compliance with the arbitrary RFCs implemented by Californium.
Most work has been spent on improving/stabilizing the following features
Support for DTLS 1.2 as defined by RFC6347 plus:
- ECDSA and PSK based cipher suites required by Lightweight M2M 1.0
- Server Name Indication (SNI), Maximum Fragment Length Negotiation as defined by RFC6066
- usage of RawPublicKeys as defined by RFC7250
- optional automatic session resumption for easier transverse a NAT
- optional extended request/response matching to support long-term observations (none RFc7252 compliant)
- Blockwise transfer as defined by RFC7959
- Observing resources as defined by RFC7641
- early/experimental (currently not complete) implementation of CoAP over TCP (draft-ietf-core-coap-tcp-tls-09)
Unfortunately, the very limited support for multicast in 1.0 could not be migrated to this release within time.