I got closer to the result. Although I delete all the files and folders from wp-includes (including meta.php) and upload the newest wp-includes, somehow it turn back to old wp-includes/meta.php after a while. Today I just replaced the meta.php and it worked, no need to delete and upload whole wp-includes and wp-admin. But I’m sure that it will change again to old meta.php after a while. I deactivated the Yoast SEO plugin, I though it was causing this problem, but it was not apparently. Now I deactivated the Display PHP Version plugin, we will see the result after several hours. But do you think a plugin cause the problem? If it so, what is your guess? We know it’s not Akismet. What else?
