Just install Xcode 3.2.2, which does include support for the Simulator 3.1.3.
You can get it from http://connect.apple.com/ - select Developer Tools, find 3.2.2. in the page, download it, and install it to a directory other than the default /Developer, so your existing tools won't be affected. You might want to skip the installation of the developer utilities, since the ones from the current Xcode will be more up to date.
But you still are missing an important point. The Simulator is not an emulator. It does not run the same instruction set as the device itself. So the best way to test is still with actual devices running the versions of the OS you are interested in testing.
I absolutely I agree testing on a device is necessary. In fact I use push notifications which cannot be tested at all in the simulator. It is also true with the Android emulator. As an emulator it is closer to a device but still not the same.
However the bugs I had would have been picked up in the simulator.
Thanks for the pointer for the older version of Xcode. That would have been great but at this point I may as well do my 3.1.3 testing on the device.
Just install Xcode 3.2.2, which does include support for the Simulator 3.1.3.
You can get it from http://connect.apple.com/ - select Developer Tools, find 3.2.2. in the page, download it, and install it to a directory other than the default /Developer, so your existing tools won't be affected. You might want to skip the installation of the developer utilities, since the ones from the current Xcode will be more up to date.
But you still are missing an important point. The Simulator is not an emulator. It does not run the same instruction set as the device itself. So the best way to test is still with actual devices running the versions of the OS you are interested in testing.