The version 2.6 is the 14th release of RPi-Monitor and the first to be available in the store.
Next versions will also be installable from the store...
The dedicated page is available here : http://store.raspberrypi.com/projects/rpi-montor.
RPi-Monitor will continue to be installable using the standard process using the .deb package which have the advantage to not be dependent of any Graphical User Interface.