Please update your profile to show which device you currently use. Your profile says 8120.

As for how it will work, read through the 9100 section and see what other users have said. From what I have seen, the device will run slower since it was not made for OS 6, plus it doesn't have all of the memory and horsepower that the OS6 devices have.

As for apps and themes, those are generally device and OS specific. Some may work, others may not. You should contact the developers directly or check App World to see if there are compatible versions for you.

However, IMHO, if your device works now as you want it to work and as yu need it to work, it really is not broken and doesn't need to be fixed with an OS upgrade, even to OS 6.

I have a 9105, the UK model. OS6 provided a couple of bug fixes.

My keypad sometimes used to register two button presses instead of one; very annoying, especially when trying to use the calculator. It seems much better now. Also, I used to have a problem with text messages repeating themselves when a chat got longer than about 20 messages, but this is ok now.

All my apps were kept during the upgrade, but I had to change my QR code reader, and the Facebook app doesn't work quite so well as it used to.

1. You'll have "better look" on OS6, many change in menu view etc
2. Coz some bug on OS 5 have fixed OS 6
3. No you aren't. You have to use theme for OS6 only