Apple Time capsule is a multipurpose device used as an access point. It is also used for backing up data. Time capsule flashes yellow when there is an update available. Follow the steps mentioned below for
time capsule flashing yellow. There is a firmware update required. Open a web browser and type the default IP address and login to the device. Then go to the applications. Click on utilities and from the drop down menu select Airport utility. There will be a pop up regarding software update. Click on that and update the firmware. Restart the device.