XenForo till 2.1.9 still uses deprecated HTML language tags for Chinese locales like "zh-CN", "zh-TW", "zh-HK". At least, this hinders Safari from picking up correct Chinese fallback fonts. (in vBulletin 3.8 this is user-editable, but in XenForo it is only a dropdown menu, hence the necessity of...
xenforo.com