Quote from benifin
no major FW changes for some time now
Just looking back at my Firmware saves folders...
3.1.4 to 3.2.0 was fairly quick, from Oct 10th 2015 to Nov 13th, 2015.
But from 3.2.0 to the release of 4.0.1 beta release was April 10th, and the full release was not until Sept 28th, 2016.
So thats a pretty wide spread from release to release firmware wise.
The last release was Dec 18th, 2017, so going by the above (still pure speculation of course), we are not due for another OS update until May of 2018...