A year or two ago I've set up my GA4 property in Google Analytics and it did not require changing my code snippet, so my website is still using the old UA code snippet for the GA4 data flow (which works fine - I see in GA4 that my data collection is active).
However I wonder if I should change the old snippet currently used on my site:
<!-- Global site tag (gtag.js) - Google Analytics -->
<script async src="https://www.googletagmanager.com/gtag/js?id=UA-XXXXXXXX-1"></script>
<script>
window.dataLayer = window.dataLayer || [];
function gtag(){dataLayer.push(arguments);}
gtag('js', new Date());
gtag('config', 'UA-XXXXXXXX-1');
</script>
And instead use the new one:
<!-- Google tag (gtag.js) -->
<script async src="https://www.googletagmanager.com/gtag/js?id=G-XXXXXXXX"></script>
<script> window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag('js', new Date()); gtag('config', 'G-XXXXXXXX'); </script>
Does that make a difference?