It's no secret that the budget Nokia Lumia 520 has been the best selling Windows Phone - a 4" screen and terrific gaming performance and build quality for a sub-£100 pre-pay smartphone has seen it sell in the tens of millions worldwide. And, although we don't want to put up a news story for every device that gets its Lumia Cyan firmware update, I'd like to record, with photo proof below, that the 'mighty' Lumia 520's Cyan rollout has now started in earnest.

Begging the question, of course, of whether it's best to get a Lumia 520 that's older and cheaper, or a new 630 that's newer, more expensive and yet with both devices on exactly the same OS version? There are pros and cons for each, but see my review of the 630 for a few pointers either way. (Plus my comparison of the 630 with the 625.)

The 530's PAYG price in the USA was under $40 this week, under a special offer - -simply astonishing for a smartphone with this much power, relatively speaking, with worldwide satnav, a decentish camera, capable of playing most games, and so on. The cheapest in the UK as I write this is £65, but I've seen it below £60 in the past.

And now with Lumia Cyan on (here's our summary of what's in it), there's all the benefits that this brings to the UI.