Now, or soon, from PS Audio. Should be interesting. 
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The best buy in audio - free.
For state of the art.

Ted has done it again.
Glad to hear of your success! It is indeed an interesting improvement. It appears this is the last upgrade of this unit. It will be interesting to see what the next generation unit brings to the table. 
I'm loving Sunlight!  It's a new DAC.  Hearing snappier transients, purer (leaner?) bass, more cleanness and general transparency, slightly more energy from the upper mids to the highs.

Soundstage came forward about four feet.

I've never had a problem installing an update.
To fuzztone,

Sorry for the delayed response.

I simply followed the "README" instructions found on the SD card after the Sunlight download.

Download the Sunlight files to your PC. They are "zipped" so must be extracted. Once extracted, select them all and copy them (Control C) to your clipboard.

Make sure you wipe all existing files from your SD card, then  paste the new files (Control V) onto your blank SD card.

Shut off your DAC using switch on rear. Remove ethernet connection and I2s connector (if used). Insert your SD card (pins facing up, i.e. upside down) containing Sunlight files.

Turn on DAC using switch on rear. The square blue standby button on front panel, left side, will blink during installation then you will see the "intiialization" screen. Once the initializing has ended, the DAC will display it normal operational screen.

Using your remote, reset the DAC volume control to 100 (from the default value of 25).

You should be good to go at this point.

Good luck and happy listening!