An Avian Securities note released to Business Insider claims the iPhone 5 won't begin production until September, meaning a release is likely at the end of 2011 or in early 2012.
The information is said to come via a tip-off by "a key component supplier" Apple is using for the iPhone 5.
The specs of the new phone aren't known. Avian also reports of rumours pointing to a lower-spec and lower cost iPhone.
All previous iPhone models have been introduced in June or July, which had led to earlier speculation of a summer reveal this year. A winter launch would certainly go against the Apple convention.
We could see the launch of a cheaper model in the summer, with a higher spec iPhone successor hitting in the winter.