Changes.rst has not received an "2.7_beta1" section - it has the
"highlevel" overview of what is new in 2.7, but for alpha/beta releases
it's better to look at git log to see what has been added/fixed.
New features alpha3 -> beta1 are
- a large number of signed/unsigned related warnings have been fixed
- bugfixes in --dns-updown script for linux systems using resolvconf
- rewrite of the management interface "bytecount" infastructure to better
interact with DCO
- PUSH_UPDATE server support (via management interface)
- introduction of route_redirect_gateway_ipv4 and _ipv6 env variables
- speeding up t_client tests by reducing per-test startup delay 3s -> 1s
The biggest noticeable difference in beta1 is the reformatting using
clang-format, leaving uncrustify as that wasn't stable across versions.