As of today Microsoft is releasing a preview of their Windows Phone SDK which allows for devices running as low as 256mb of memory. This is to help spread growth in 23 additional markets including, “Bahrain, Bulgaria, China, Costa Rica, Croatia, Estonia, Iceland, Iraq, Israel, Kazakhstan, Latvia, Lithuania, Qatar, Romania, Saudi Arabia, Slovakia, Slovenia, Thailand, Turkey, UAE, Ukraine, Venezuela and Vietnam. “ The Nokia Lumia 610, a budget device with 256mb was also announced. We’ll have more, including what the 256mb threshold means for existing apps, in the near future.
Source: The Windows Phone Developer Blog