probably just a few minor bug fixes. you could likely reinstall the 3.8 OS onto the handheld and would have gotten the option to install Password Keeper.
also, just keep in mind that the providers in Hong Kong tend to release their software very early on. i would say they release the 'release candidates' whereas others would prefer to beta test a bit more before releasing the software on to their customers. its a difference in the various cultures, i would think.
you can see the differences between the Apps 4.0 versions between the different providers. more testing will equal less support (wishful thinking). i guess that could bring into question the level of support (or the wages of support reps) in SE Asia.