Error : wpcf7_add_shortcode is deprecated

I get the following error on my site:

wpcf7_add_shortcode is <strong>deprecated</strong> since Contact Form 7 version 4.6! Use wpcf7_add_form_tag instead. in /nas/content/live/company/wp-content/plugins/contact-form-7/includes/functions.php on line 355

How can this be remedied? Any large files cannot be uploaded and I get “There was an error trying to send your message. Please try again” notification.

Thanks,

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