I'm working on various phones with all the updates (SE,6,6s,7,etc) From what I know there are minimal to no issues with any of the phones that have been updated since. Have you don't any service to your unit prior to the new OS Release?
My best solution for this is to back up your phone and to restore and update it via Itunes.
I only had to do this with one phone, which may have resulted in poor downloading of the new update.
Hope this helps, but let me know if it works.