Nokia was working on Android-powered Lumia handsets before it sold its mobile phone division to Microsoft.
According to the sources, the Android Lumias were “up and running” long before Microsoft bought Nokia’s mobile phone and services business last month.
Microsoft paid $7.2 billion for the company’s handset division.
The report claims that Microsoft was aware of the Android Lumia’s existence during early discussions, but were never part of the negotiation.
Nokia originally sided with Microsoft’s Windows Phone operating system after warning that there was a “very high risk” could become dominated by one single company.
Time has shown that to be true, with Samsung accounting for four in every five Android handsets sold.
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The report does not stipulate whether Nokia had any plans to launch Lumia handsets running Android, or if it was simply an internal experiment.