MacBook Air 
About the security content of OS X Server v4.1.5
Learn about the security content of OS X Server v4.1.5.
If you see an alert in iTunes that says "There was an error downloading your purchased music"
You may see this alert when you try to download purchased content from the iTunes Store: “There was an error downloading your purchased music. An unknown error occurred.” Learn how to resolve this issue with the steps below.
If you see error 1415, 1417, 1418, 1428, 1429, 1430, 1436, or 1439 when restoring or updating an iPod in iTunes
When you restore or update your iPod in iTunes, you may see an alert that says “An unknown error has occurred” followed by the number 1415, 1417, 1418, 1428, 1429, 1430, 1436, or 1439.
Apple certifications: Getting certified (Canada, Latin America, United States)
This article describes the service certification offered by AppleCare and explains how to register to take service certification exams.
Specific time zones might not sync calendar events from iOS 8.3 to Microsoft Exchange
Events you create in some time zones where daylight saving time is used might not sync to Microsoft Exchange.
Get help with WeChat
If you have a question about WeChat, you can look for it—and the answer—in the app’s help section. You can also visit the WeChat support website or call the hotline.
If you can’t see Apple Music playlist, album, and artist images on your iPhone, iPad, or iPod touch
To see playlist, album, and artist images in Apple Music, your iPhone, iPad, or iPod touch must be connected to the Internet.
