I've been looking around on seeing if people still use the Oppo Sonica DAC and I was one of the hold outs still trying to squeak out a few more years out of this unit.
I still have an old iPad that won't update anymore so the Sonica Control App is still functioning on it. I lost the App on my new iPhone once I upgraded recently. My unit has this mod on the single end (wish I had done it for balanced too now)
http://tweakaudio.com/EVS-2/Oppo_Sonica_DAC_mods.html
Suffice it to say, I have put new life into this DAC when paired up with a newly purchased Eversolo T8. I've disabled the wireless and Bluetooth and even unplugged the wireless networking module on the inside and it sounds pretty good, much better than a stand alone wireless streamer now....and I have gapless finally! So if you are looking to get a bit more life out of your Sonica DAC, you might consider making it a dedicated DAC and add a new streamer device. I'm really quite surprised how much better it sounds. Currently using the USB interface for the T8 but have other devices hooked up to the Coax (Oppo 105) and Optical from television and have the little remote that you could buy for the Sonica to switch inputs.