To sum up the link below. There were alot of rumors going around saying that phones like the Lumia 900 would not be compatible to upgrade to Apollo later this year. I hope this is wrong but the way they are making the OS apparently it won't be able to handle it. It will apparently have to have a dual-core chip with higher-end graphics card in it. Microsoft still has whether to confirm this is true or not.

The full article is below:

Microsoft evangelist made a mistake on Windows Phone 8 upgrade claim - Crave - CNET Asia