Some of your <a href="[changes_url]">core files</a>  were changed manually. That can lead to various problems, especially when upgrading to a new version of [product]. To learn more about why we advise against changing the core files, please read this <a href="[docs_url]" target="_blank" >article</a>.<br><br>[product] automatically checks for changes in core files every time you log in. To disable this check, go to <a href="[settings_url]">Settings → General</a>  and untick the Monitor changes in core files checkbox.