Even numbers are development versions.
example
2016.0 is a development version. At it's given time it gets released as 2016.1
Once 2016.1 IS released, then the development version jumps to 2016.2, looking ahead to release 2016.3
You will get 2016.3 by keeping updated with the development bleeding edge
You can use nightly builds (macOS or Windows) to install development edges (knowing they can be unstable, but they will have fixes that will be present in the following stable too)
Or you can wait for the next release. That one will contains those fixes... but further tested.
Right now you can get the prelease of 2016.4, on the nightlies (windows or Macos)
http://download.flightgear.org/builds/nightly/Finally, for linux, you are better off compiling yourself, althouth saircot offers a PPA for development following, which works in ubuntu
https://launchpad.net/~saiarcot895/+archive/ubuntu/flightgear-edge