Recently I upgraded my phone (Sony Ericsson Xperia Mini Pro) from Cyanogenmod 7.2 to Cyanogenmod 9. And you should upgrade too, if you are running Cyanogenmod 7.2. This is why:

• The hardware keyboard layout can be configured from the settings menu.

• The ‘symbols’ key on the hardware keyboard now actually works, so you don't have to switch to the software keyboard anymore when you have to enter an exotic symbol.

• The dictionary on the software keyboard now works. Not that I ever use it, but hey, it might be useful for some of you.

• The ‘dock’ at the bottom is more stable: it doesn't disappear for no reason, and the icons in it stay where they are.

• Dragging icons from the app drawer to the main screen is a lot smoother.

• CM 9 (based on Android 4) looks way cooler than CM 7.2 (based on Android 2.3).

But I went to some pain while upgrading the thing. So if you want to perform a similar upgrade, here are two useful tips.

The first one: Be sure to put not only the roms of CM 9 and the Google apps on your SD-card, but the ROM of the old CM 7.2 as well. If anything goes wrong, you can quickly flash the old image for having access to your phone again.

Second thing: before flashing CM 9 to your phone, you'll probably have to upgrade your boot loader. I didn't do that, and after flashing the ROM, the phone booted into a black screen; removing the battery was the only option. Maybe you can upgrade the boot loader with ROM manager, but I didn't try that. I just used fastboot (a tool that can be found in the platform-tools folder of the Android SDK), as described in steps 5 and 6 of the excellent documentation on the cyanogenmod wiki.

The new bootloader looks much slicker than the previous one, which was plain ugly :-). And when it's installed, you should be able to flash the roms for CyanogenMod 9 and the Google Apps for Ice Cream Sandwich. (But don't come after me if things break, because I'm clueless as always.)