Updating WordPress and PHP

So I have followed you instructions to update to the most recent version of WordPress and it tells me that the sites PHP needs to also be updated. I went to my host (Hostgator) and updated it to version 7. This caused my site to not work at all. In fact, I couldn’t even see it. Because of this, I reverted to the older version and my site was reactivated. Is there something I am missing? How can I get around this? Thanks for your help.

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