UPDATE IOS

I PURCHASE A IMAC AND IM CURRENTLY USING, IOS SAFARI 13. 10. 2. I NEED TO UPDATE TO A CURRENT SYSTEM IOS TO MOJAVE , OR HIGH SIERRA TO DOWN LOAD MUSIC APPS, CAN YOU OFFER UP SUGGESTIONS, AS TO HOW I CAN MOVE FORWARD, TO RECEIVE A CURRENT UPDATE. IM NOT IN A POSITION FINANCIALLY, TO PURCHASE ANOTHER COMPUTER.

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