So the best thing on a live site is to turn off the display of errors, as they can contain information that ideally should not be exposed to members of the public.
Turning off the display of errors can vary from hosting environment to hosting environment, so do check in with Hostgator to find out how to do this on your site.
Regarding the deprecated function, we’re definitely working to clean up the codebase of our plugins with each release in order to catch things like this. However, the error message is really just a means of PHP warning us that a particular part of the PHP language should no longer be used – it will actually still function as expected.
So, in this case, the best approach is to turn off the display of errors.
I hope that helps but let me know if you have any further questions.