Hi Neon Developers, KWin will upgrade the minimum required libinput version to 1.5 which was released in September, see https://lists.freedesktop.org/archives/wayland-devel/2016-September/031054.html Version 1.5 provides several new features which KWin needs to use for a good experience, thus we will soonish increase the version requirement.
Since today and with https://cgit.kde.org/kwin.git/commit/?id=7f16d83e046b3a80aa60e958b68d002e17eaeb0b KWin requires Libinput 1.5 to build. I got it to work on my Neon Dev Unstable system without problems with the 1.5.1-1ubuntu1 source from https://launchpad.net/ubuntu/+source/libinput So this should also work on the automatical build.
https://phabricator.kde.org/T4577 FWIW you can simply create tasks on the neon workboard. We'd track the work there anyway.