Why doesn`t itunes sync with my iphone after I updated it to the new version of Itunes

Maybe it doesn't like you any more.

If you have an actual issue, try searching for the specific error that is occurring.

I am having same problem. Updated my ITunes and now my 4s updated to ios8 isn't even recognised. Plus iTunes is telling me it is no longer compatible with my computer. (windows 7). Have removed all Apple software & reinstalled but no results.