I don't know why Google jumped to having a desktop version but is there away to go back to the mobile version? I have the iPhone 5s with the new update I prefer the mobile version better then the desktop one on my iPhone
Google did nothing, Stack Exchange sites can be viewed both in a mobile and full site version.
You accidentally tapped the 'full site' link in the footer. There is a corresponding 'mobile' link in the full site footer, tap that and get back to the mobile view:
The preference is stored in a cookie, per site.