Having now an automatic way to create a ticket in the documentation repository
for each new feature in QGIS, we are sure that all new features is now in the
documentation.
The documentation team worked hard on three releases of QGIS: 2.10, 2.12
and 2.14 so the documentation is now up to date for the current Long Terme
Release of QGIS. This is around 180 new features that have been documented in
4 months.
If you think there are some missing features in the documentation, feel free
to add a new ticket, write small text to describe it or better push a
contribution.
The documentation team will now work hard the next months to document the
current stable release (2.16) of QGIS.
Check the 2.10, 2.12 and 2.14 milestone to see all the documentation work that has taken place:

• https://github.com/qgis/QGIS-Documentation/milestone/5
• https://github.com/qgis/QGIS-Documentation/milestone/4
• https://github.com/qgis/QGIS-Documentation/milestone/3