If you're interested in cutting edge Construct features try the Beta releases. These releases should not be used unless you are willing to tolerate some bugs.
Re-land the architectural change originally made for r38
Themes support, usability improvements, architectural changes
Back button support on mobile, popup remote preview, more bug fixes
Access codes, split Cordova exporter, and more.
More bug fixes and some usability tweaks
SVG raster size, background cloud uploads, more usability improvements
A number of usability improvements
A big batch of changes, compatibility, and bug fixes
Windows UWP export update, some more additions, and even more bug fixes