+ Experimental feature: support for out-of-process volume plugins

* The userland proxy can be disabled in favor of hairpin NAT using the daemon’s `--userland-proxy=false` flag

* The `exec` command supports the `-u|--user` flag to specify the new process owner

+ Default gateway for containers can be specified daemon-wide using the `--default-gateway` and `--default-gateway-v6` flags

+ The CPU CFS (Completely Fair Scheduler) quota can be set in `docker run` using `--cpu-quota`

+ Container block IO can be controlled in `docker run` using`--blkio-weight`

+ ZFS support

+ The `docker logs` command supports a `--since` argument

+ UTS namespace can be shared with the host with `docker run --uts=host`

* Networking stack was entirely rewritten as part of the libnetwork effort

* Engine internals refactoring

* Volumes code was entirely rewritten to support the plugins effort

+ Sending SIGUSR1 to a daemon will dump all goroutines stacks without exiting

+ Support ${variable:-value} and ${variable:+value} syntax for environment variables

+ Support resource management flags `--cgroup-parent`, `--cpu-period`, `--cpu-quota`, `--cpuset-cpus`, `--cpuset-mems`

+ git context changes with branches and directories

* The .dockerignore file support exclusion rules

+ Client support for v2 mirroring support for the official registry

* Firewalld is now supported and will automatically be used when available

* mounting --device recursively