I have no issue connecting with Apple's newest software. You most likely have more an issue with the phone. When you upgrade your software for the iPhone, it stacks the new software on top of the old. Since you have an iPhone 4, you probably have at 3 different operating systems on there. The fix is pretty simple but takes two hours. Do a manual back up of your phone to your computer, not just a synch (10-20 minutes). Then hit the restore iPhone button. This completely erases the memory and only installs the latest version of the software. It will then ask if you want to set the phone up as a new iPhone or from a previous one. Select your previous iPhone and it will configure it exactly to where it was when you did the manual back up on it.
My wife had issues with her iPhone 5s after the last system upgrade. Battery dying in 45 minutes and really, really hot. Had to put it in the fridge. I thought it was a failed battery. $79 later, new battery but still the same problem. They did the above procedure to her phone except through icloud and it fixed her problem immediately. It's like she has a new phone again. Great battery life and faster. The downside to doing it through iCloud is that it doesn't set your phone up identically to the way it was before the procedure. Lots of re-downloading stuff and set up. Doing it through your computer is so much faster.
I did this to my iPhone and iPad yesterday and have noticed a significant improvement in both. Hope this helps.