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what is the final version of ios 11
The final version of iOS 11 was iOS 11.4.1.
when was ios 11.4.1 released
iOS 11.4.1 was released on July 9, 2018.
how did the version 11.4.1 improve iOS
iOS 11.4.1 improves reliability of syncing mail, contacts and notes with Exchange accounts.
what did the version 11.4.1 of iOS fix
iOS 11.4.1 fixes an issue that prevented some users from viewing the last known location of their AirPods in Find My iPhone.

Question: what is the next version after
Self-contained rewrite: what is the next version after 11.4.1 of iOS