Q: Problem synching new phone to computer

Are you using iTunes 12.4 (current version)?

This is a major issue.

You need a current version of iTunes to communicate to iOS 9.  Get it at:

http://www.apple.com/itunes/download

However, getting this requires you to have OS X 10.8.5 on your Mac, or Windows 7 on your PC (or later).  It sounds like you have an old operating system.

Correct.

If you have iTunes 11.4, that means that is the highest version your old operating system can support.

You must therefore use a later version of your operating system if in fact your current iTunes is 11.4.

I suggest posting as much detail as you can about exactly what computer and operating system (and versions, years, etc.) you are using.

If you have a Mac, it could be that it is too old to upgrade.  Or perhaps we can tell you how to upgrade.  With Windows, maybe someone can offer similar assistance.

If your iMac is from mid-2007 or newer, it can run the current version of OS X (El Capitan, OS X 10.11.5).

Upgrade to OS X El Capitan - Apple Support

It is not listed as an update, because major changes in OS X  versions are considered upgrades.  Snow Leopard is now about five years old, and there have been upgrades available to OS X about once a year since (Lion, Mountain Lion, Mavericks, Yosemite, El Capitan).

Good luck with it.  Remember you are doing five years' worth of updates / upgrades in one massive action.