PHP Notices and PHP Warnings are harmless. They are not errors, they are just a messages to developers informing them about some things that might require attention. Since Notices and Warnings are not errors, they do not require immediate fixes or solutions. Only developers should see them. If you are are seeing notices and warnings, it means that your server is in DEBUG mode. You don’t need DEBUG mode if you are not a developer, so please take your site out of it. There are many ways to activate DEBUG mode, so please turn it off the same way you turned it “on” or consult your server admin if you don’t know how to do it.
PS: Yes of course we are paying attention to all Notices and Warnings and making all necessary fixes or changes. We just mean that notice or warnings does not require an immediate fix. Please put your site in regular non-DEBUG mode, so you won’t see them.