Leaf Smart System Upgrade (SSU) provides the ability to upgrade the EOS image with minimal traffic disruption.Note: It is possible that SSU shutdown and bootup are not supported in the same image. If a product has shutdown support in image A and bootup support in a later image B, then SSU upgrade cannot be performed from image A to any images earlier than image B, including image A itself. However, upgrading from image A to image B onwards is allowed.