Can Flex Viewer 1.x access ArcGIS Server 10.1?

Hi, my organization's Flex Viewer is still based on Flex Viewer 1.x with Flex SDK 3.4. It has been working fine with ArcGIS Server 9.3 and 10.
We are still trying to migrate the Viewer to the latest Flex Viewer 3 version, but have not completed yet for some reasons, and I am wondering if the current Viewer on 1.x can run on map services published by ArcGIS Server 10.1. Does anyone know about this?

Thanks,