Windows 10 flagship allegedly coming 'later this summer'
Upgrades to Windows 10 for smartphones should also start by the end of summerWe’ve earlier heard Microsoft execs officially say that new devices are coming later in 2015, but we did not know what is the exact time-frame that they envision. Naturally, if Microsoft were to indeed release a new flagship in summer 2015, we expect this to happen at the very end of the season.
Good news is that - unlike the situation with the non-existent transition to Windows Phone 8 - all current Windows Phone smartphones will get a free upgrade to Windows 10.
source: Windows Central