Let's face it -- Microsoft has placed a lot of focus on Windows 10 for desktop, neglecting its counterpart Windows 10 Mobile. But rest assured, Microsoft has plans to ramp up the testing process for Windows 10 Mobile once Windows 10 for desktop ships in late July.
According to Microsoft's Greg Sullivan (he's the communications director for Microsoft Devices), the Redmond giant will place focus on Windows 10 Mobile in early to mid July. Since Microsoft's development teams are all focused and working on the same operating system, they can be easily reallocated to add features or squash bugs. Clearly the focus has been on Windows 10 for desktop, but as the release date nears, Microsoft will begin shifting towards the mobile side of things.
The most recent Windows 10 Mobile build is build 10136 and it was released on Tuesday, June 16th. Microsoft has a lot of work to do when it comes to the mobile operating system, and the company has to work extra hard to polish the operating system in order to prove that Windows 10 Mobile is infact a viable competitor to rivals Android and iOS.