Upgrading 3.7.1 page not found errors

Hello,

I inherited maintenance of a site that had not been kept up and is WordPress version 3.7.1. I have been able to successfully update all the plugins and theme to the most recent version.

The upgrade available for the WordPress in the dashboard is WordPress 4.2.3. I have tried twice to run this update and both time once it is completed it delivers “Page not Found” on all of the admin pages. Luckily I have been able to roll back to 3.7.1 so I am able to manage the backend.

I am assuming that the “jump” between the versions is to great for the code to handle, but that is just a guess.

Does anyone have any suggestions?

Is there a way to gradually upgrade from one version release to the next until it can “catch up” to the latest version.

Thanks.
JS