Microsoft have released new firmware for the Surface Pro 3 but don’t get to excited. The September update has just a new USB 3 card reader driver which improves the system power usage when an SD card is inserted. There are no other changes so no Wifi improvements or better Windows 10 support.
Here are the details from Microsoft:
September 2015 updates
The following update will be listed as “System Firmware Update – 9/15/2015” or “System Hardware Update – 9/15/2015” when you view your update history.
When Surface updates are provided via the Windows Update service, they are delivered in stages to Surface customers. As a result, not every Surface will receive the update at the same time, but the update will be delivered to all devices. If you have not received the update then please manually check Windows Update later.
USB 3.0 Card Reader driver update (v10.0.10240.31217) improves the system power usage when an SD card is inserted.