Update your PHP
Simple and easy.
Is your website hosted here at WA. And if so,do you keep getting the message on your site dashboard that your PHP needs to be updated. If so , all you need to do is go to site support .
Just let them know your PHP needs to be updated and which site it is and they will handle it from there .
Just remember not to make any changes to your site until the finish your transfer to the new server .
I hope this helps.