Yesterday I was testing the speed of my site (decozyhome.com) with the google tool “PageSpeed Insight” and I noticed that, in the best practice section, I had a red warning about API usage telling me that I use a Deprecated API.
I think the best approach might be to contact the app developer with this issue by email at: bydbest@gmail.com and ask them to update their app if it’s causing this issue.
From looking into this a bit further it seems like the deprecated API is being called on a web pixel manager script file that is part of Shopify. I’ll connect with our internal devs on this - however the warning that PageSpeed insights does not flag this issue in the performance section on the report, but in the general best practices section. So there should not be any negative performance impact that customers would experience when browsing your site, caused by using XMLHttpRequest.