Hi Sara,
Thanks for taking the time to report this.
I’ve just checked the deprecated functions on our plugins and here’s what I found:
The WC_Cart::get_cart_url() function was being used in our Event Tickets Plus plugin, but we’ve already replaced it by wc_get_cart_url() to prevent PHP notices in version 4.5.6, so you shouldn’t get that notices if you are using latest versions of our plugins.
As for the add_to_cart_fragments, we do not use that in any of our plugins. Could you please check where that message is coming from?
You can enable WP_DEBUG and WP_DEBUG_LOG to create a debug.log file inside the /wp-content directory. After that, try reproducing the issue a few times, so that it saves into the debug.log file. Please share that log file with us so we can see where the error is coming from.
Also, please share with us your system information by following this guide > https://theeventscalendar.com/knowledgebase/sharing-sys-info/.
Thanks,
Victor.