Apple regularly releases major new versions of their mobile operating systems and in October of 2018 they released iOS 12.  iOS 12 supports most every device that supported iOS 11 and so if you are running iOS 11 you should be able to upgrade. 

OWT evaluates the iOS releases and we support a lot of users that have upgraded. The past few releases Apple has offered beta releases to the public which we had hoped would make the final versions less prone to bugs but it seems that they start with such a terribly buggy product that by the time the final release is made available a few bugs still make it through.  

Since version 9 of iOS OWT has recommended that users wait for the ".1" release to upgrade and this year is no exception.  Now that iOS 12.1 is out we do suggest that all iOS users upgrade to this version.