Upgrade Skin Warning

Hello!
I’ve tried to login to my Mojo Marketplace, but could not even though I’ve got the purchase ID and so on.

I’ve managed to get their CS team to reply me, and they sent me via email instead.

However, it seems that the file they sent me is not the latest one, because I saw the date of “class-install-plugins.php” is from december 2018, and after I replaced that file to my site via FTP, it still shows the same error message.

Would you help to take a look? I’m not sure what to do now.

Or can you send me the latest class-install-plugins.php instead so I can replace it?

I look forward to hearing from you, thank you.