Install If You're Dealing With An iOS Problem
If you're dealing with a bug or performance issue on iOS 9 or an older version of iOS 10, you might think about installing iOS 10.3.3 on your device. It could have a positive effect on your iPhone, iPad or iPod touch's performance.
The iOS 10.3.3 update change log doesn't specific the exact bug fixes on board Apple's fixed in its latest maintenance release.
That said, the iOS 10.3.3 update could patch up the performance issues you're dealing with on an older version of iOS. These issues include, but aren't limited to, UI lag, bad Bluetooth, various issues with Wi-Fi, or bad iOS 10 battery life.
If you're dealing with an unfixable iOS problem on an older version of iOS, the iOS 10.3.3 update is probably worth a try.
If you skipped a previous version of iOS 10 remember that you'll also get the bug fixes from those updates baked into iOS 10.3.3.