We have fixed notice that was related to our theme file. Also, we have created ticket for the Massive Addons support team about this issue. Warnings are related to the version of PHP – 7.1. I’ll inform you once we get an answer.
Thanks for your response – it would be good to get things working with 7.1, but I can drop the PHP version back to >=7 if that would let me work on the site in the meantime. Reluctant to do this if it’s likely to mean redoing things once updates are made – could you advise?