Hello there Jason!
Do you know if your site currently has WP_DEBUG mode enabled? Turning off debug mode will ensure that warnings and deprecation notices like these are not displayed publicly to your users. I would recommend ensuring that the WP_DEBUG setting is set to false when your website is public facing/in production.
More information about editing this setting can be found here:
https://jetpack.com/blog/wp-config-php
For further context, deprecation notices like this appear to inform developers or site owners that a future version of software will include a change that will require it to be integrated differently in the future. It appears that the latest version of Jetpack Boost introduces a deprecation notice for a shared function that the core Jetpack plugin also uses – the next Jetpack update should resolve the deprecation notice and there is no danger to your site here.
Regardless, turning off debug logging on your site will ensure these messages are logged privately and not shown to your users.
I hope this information is useful, and please let me know if you have additional questions!
