The is_ajax function is deprecated since version 6.1.0. Replace with wp_doing_aj

I have the same problem. Trying to fix it since several hours.

Do you have an online store? If yes, do you also have issues with payments (except PayPal)?

Cant say because no new orders until now.. but it seems to work

Hi @dervonz and @5b4store,

There is an open issue in Github which you can follow for updates here:

https://github.com/woocommerce/woocommerce/issues/31628

However, note that PHP warnings are usually generated by themes or plugins that are still calling that deprecated function. So you may want to perform a conflict test to locate the culprit and reach out to the authors to get that fixed.

For more detailed instructions about conflict testing, check out this – How to test for plugin and theme conflicts.

Thanks.