Without much of an announcement, Sony has launched PS4 firmware update 2.04. The 207 MB update is only meant to improve the system's stability.
However, many users are reporting that they are unable to download the firmware update due to loss of PSN connection as soon as the download starts. "Some players are reporting PSN issues -- our engineers are on the case and investigating," said Sony.
We will provide you with further information when we hear more about it. For now, it's best to first let Sony fix this issue.