“Allow me to set the record straight. No. It won’t happen. Not for the Lumia 900, and not for any other existing phone. It won’t happen partially, through an update that will deliver just some features, and it won’t happen for those who wish to pay for such an update. It simply isn’t happening. Sorry. But please don’t email me about this; I’m just the messenger”.
There has been quite a bit of conflicting reports regarding the upgrade path of Windows Phone 7.5 Mango to Windows Phone 8 Apollo. Some reports have suggested that Microsoft would be ignoring older devices and focus Windows Phone 8 on newer handsets of the dual-core variety, and at one point Microsoft developer evangelist Nuno Silva actually said outright that all Windows Phone devices will receive the Apollo update. He then retracted his statement which seemed to lend itself to the growing suspicion that Windows Phone 7.5 devices will not be seeing the Apollo update.
So it looks like if you were thinking of getting your hands on a Windows Phone device, perhaps holding out till Windows Phone 8 might be a good idea least you get stuck with a handset that cannot be upgraded. However, until Microsoft actually makes the official announcement, we will keep the speculation down to a minimum for now.