Windows 10 Mobile build 10559 currently in testing by Microsoft

[Windows Central]

Microsoft continues to work on Windows 10 Mobile, and a new build has hit the company's internal Fast distribution ring. According to Windows Insider head Gabriel Aul, the current internal Fast build is 10559.
Responding to questions on Twitter, Aul said this:

10559 is in internal Fast ring now.
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Full story from the WindowsCentral blog...