Is there a way to update simulator to iOS 9.3.1??

If you update xcode, the simulator should update with it.

Which version Xcode are you using?

The short answer is no. You get whatever version comes with your Xcode version. They can't be upgraded like real devices. As noted by other posters, update to the latest Xcode for the latest simulators.

In the past Apple has not provided simulators for all the x.y.z point releases, just the relatively major x.y versions (e.g. 8.1 but not 8.1.1, 8.1.2 etc.)

The problem is that my app is crashing in devices running 9.3.1 and I can't reproduce the error :/

We did not ship iOS 9.3.1 nor iOS 9.3.2 simulator runtimes.

when update for 9.3.1 will come ??

Why do you think you need it?

Because our production devices was forced to upgraded to 9.3.2. However, we can only use 9.2. simulator on our local and pipeline for testing purpose. Does Apple have any ETA on releasing 9.3 simulator in xocde again? or is there any way to downgrade the prod devices back to 9.2?

Need to test translate3d transitions in Safari. These are available on 9.3 but not 8.x.