PCBNew4.0.6 pcb File Compatibility Linux64b-to-Windows10/64b Issue

Ok I have posted the whole file on DropBox here:

My friends Linux version is given as:

2016-08-20 BZR 7083

My understanding is that it is shown on the download site for Linux Ubuntu as the most recent stable release which I understand is 4.0.6 for Windows. I wonder why it has a BZR build number rather than 4.0.6. Should the Linux Ubuntu build also show 4.0.6 as the version number? What is a BZR version - does it refer to a pre-release version?

In any event it seems odd that older Kicad pcb files are not compatible with more recent software releases.

Thanks for clarifications!