Windows Phone 8.1 is the massive OS update from Microsoft. Lumia Cyan is the corresponding firmware from Nokia, customized for individual hardware. The two go together and are part of the official over-the-air update expected later in July and rollout through August.
Popular internet leaker @Evleaks has posted what looks to be a schedule of the Lumia Cyan update, broken down by device e.g. Lumia 920 and Lumia 1520. However, this is only for the Benelux region, which is comprised of Belgium, the Netherlands and Luxembourg.
As expected, new phones like the Lumia 630, Lumia 635 and Lumia 930 come with Cyan and Windows Phone 8.1 out of the box, so they are naturally first. Other Lumia devices have their firmware completion dates set for the end of June, with rollout to begin at the end of July through August.
- June (4th week) Cyan completion – Lumia 925, Lumia 1020, Lumia 1520
- June (5th week) Cyan completion – Lumia 520, 620, 625, 720, 820, 920 and 1320
Rollout for the over-the-air update won’t take place until a month later, with most updates beginning on the third week of July and continuing through the beginning of August.
The big caveat here is that these dates are for ‘open market variants’ and not – we repeat not – carrier branded devices. As the document notes, those dates are subject to change, pending final approval.
Carrier branded phones are presumably on a more nuanced and varying schedule, though the above timeframes should give you an idea of relative availability.
We have not been able to independently confirm the above dates specifically, but it certainly seems likely from our internal information. The information came to Evleaks through a tip.