And by swf11.1 runtime I mean an OpenLaszlo, with support for 11.1, 11.2, 11.3 within the same version of the server.
When I asked the question on the Apache Flex mailing list, which Flash Player versions most developers target at the moment, most said that you can expect a majority of internet users to be at version 11.1 or 11.2 on desktops (that was back in May). Some enterprise projects were still using 10.3 and 11.0.