It’s just big fixes. Not really worth the time if you aren’t having problems.

It was supposed to fix the Save Image low-rez bug, but I haven’t tested it.

I would take the ten minutes to upgrade. It’s bug fixes and performance improvements.

@PupnTaco made a good point. The low-rez photo bug was a big whoops. Definitely worth the update.

Careful!!!!

The current update replaces the baseband modem driver. If you have an unlocked iPhone on another carrier you’re f****d.

There’s also no way of undoing it, as the baseband resides on a different part of the hardware, and a factory reset will not revert the baseband to an earlier version.

It’ll screw both soft-unlock via yellowsn0w and those TurboSim applications. If you’re unlocked, don’t update.

Jalbreaking is very close to my heart. If you ever plan on doing this, DO NOT UPGRADE, as @TaoSan said.

Actually, jailbreaking is fine, QuickPwn was out only one day after the update was published. So you can still jailbreak without problem.

If you must have 2.2.1, there are now modded installer packages popping up everywhere, that will update the OS without touching the baseband.