iOS developer here. 3.0->4.0 is the biggest jump in product history. 4.1 is just a bugfix / Lion support / couple of new widgets release. It doesn't appear (

iOS developer here. 3.0->4.0 is the biggest jump in product history. 4.1 is just a bugfix / Lion support / couple of new widgets release. It doesn't appear (warning: no release notes yet) that 4.1 runs on SL or that 4.0 runs on Lion, so run the version appropriate to your OS.