Windows 10 Mobile on track for most Lumia phones
Microsoft's Operating Systems Group team has added code to the next test build of Windows 10 Mobile that will allow that release to work on the majority of Windows Phones. When Microsoft released the first test build of Windows 10 Mobile in February, it was built to run only on a handful of Lumia devices, specifically the Lumia 630, 635, 636, 638, 730 and 830 phones. Microsoft execs attributed the small number of initially supported devices to the "very tight OS partitions" that left insufficient room for the installation process to update the OS in place.