No it’s not wow, whatever that means.
These 4.8 changes are subtle, some slight changes in various balances, a touch less this, a hint more that, they are not anything like ‘wow’.
Maybe some history is needed to better explain as it’s been a while since development was stopped on these so called legacy products.
During the numerous versions of firmware over the years, some effort was put into the DSP code to optimise SQ, the changes were not only fine tuned by Naim, but also a beta test group made up from us end users.
Some changes were not always improvements, some had mixed approvals - e.g. approved by NDX users but not approved by NDS users. some NDS users liked a change, others did not.
Now this 4.8 seems to have fine turned one more time & thanks to the team at Naim, they seem to have mixed the cocktail just right.
As an NDS user I would describe it as a huge improvement but am at a loss to describe why apart from greater enjoyment in listening.
Have been waiting a few days to see if the initial improvement on my NDS (not really expected, unless subconsciously) does not go away, and it is not going away… 
What I could describe from the first day as fresh (no doubt) and more “airy” presentation, I can summarize today as improved resolution and soundstage imaging, that are quite evident, and more delicate/refined upper frequencies, that are a bit more subtle to grasp… It could very well be, that my old, crazy head is playing tricks with me 
… But does it really matter if the SQ is so materially better with 4.8? Very happy with that.
I think its all physics 
Now I always thought there was a fascinating artistic side to physics…
Been producing music this evening - adding third, fourth and fifth harmonic distortion to a bass sound instrument to make it sound more pleasing, and well, more bassy on hifi equipment - fascinating stuff… and of course Ikutaro Kakehashi worked this out a few decades ago.
S
My Uniti2 just failed at the last stage, but I did a “try again” and it worked.
Is the Factory Reset necessary, will lose my wifi password?
I would only do a factory reset if it doesn’t seem to be working properly. I never used to bother.
Yes, all seems to be fine thanks - I just had to re-enter the Tidal account details.
A bit of fun tinkering with an old-school update with cable, leads and a manual 
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The Uniti2 may not be a 252/250, but it’s very engaging and a veritable bargain second hand.
Personally I have not done a factory reset, neither uninstalled the old installer. But the update was done successfully and the sound a really nice step.
So I would say the factory reset is not necessary.
In the same way, I have found using Roon and the SonoreUPnP Bridge with my NDS to be superior for internet streamed services, Tidal incl. support for Tidal Masters, Qobuz and Lossless FLAC internet radio.
The negates the requirement for the streamer in the Network player to do all this extra work, introducing additional noise into the processing (remember Naim’s stance of only wanting WAV processing to be undertaken from a UnitiServe), so all this is processed off-player and just a buffered feed is presented to the network player in WAV.
Not sure 4.8 sounds much different to 4.7, as superb but I did have the Beta release for the last month or so. Will have to do more listening.
I have also found that because I have been at home for the last 18 months, with the HiFi components powered on & used every single day, it also all got better.
It was only last week, I was away for a week for a staycation in Ireland.
Just updated NDS. It sounds fresh. More top end it sounds like. Maybe it’s because it’s been turned off for 30 secs?
But on a serious note it actually sounds different and to my ears more detailed a open. It might be expectation bias, something affecting the sound right now, like the grid, my brain being, well, my brain or something else or maybe it’s different.
That’s about my experience for 272 with 4.8 too. Not more top as in amplitude but more air, depth and details in there. Feels more easy going and less pushed. More real.
A stupid question perhaps, but the title and the texts all refer to 4.8, when I however look at my ND555 it calls the software version 3.7 - am I misssing something ?
Hi BertBird, firmware 4.8 is for ‘legacy’ streamers, meaning the old models, NDS, NDX etc.
Same here, I think some make much more out of this than it is.
What Mike-B wrote. If you go to the Streaming Audio section on the forum, you will see several topics pinned to the top of the list - different things and different version numbers for different types of streamers
Fear not, you are on the very latest firmware for your product!
We have released various different software updates in last 10 days, so the confusion is understandable.
Uniti Atom (inc Atom HE), Star and Nova, plus ND 5 XS 2, NDX 2 and ND 555 now have Firmware 3.7, adding TIDAL Connect functionality
First-Gen Mu-so and Qb now has Firmware 2.0.0, which enables continued use of TIDAL ahead of the streaming service changing its login process in December
Original Uniti and legacy streamers have Firmware 4.8 to address the same TIDAL issue.
Mu-so 2nd Generation family gets TIDAL Connect support in coming weeks.
Oh, and there have been Naim App updates, too - everyone should now be on 5.22.1 (Apple iOS) or 2.22.1 (Android)
Edit: or just look at @Suedkiez screenshot above 
Could be.
Do you have an NDS?
What he said.
Well it sounds very nice but is crashing all over the place!