Network Acoustics Products?

I’m with @carlsbad2 on this one. 
I’ll add that I owned Network Acoustics Eno Streaming System. It mellows the sound ever so slightly but it has nothing to do with digital artifacts such as harshness, glare, etc. That’s your components, speakers and or room. Don’t waste money on bandaids. Address the root cause. 

i agree with the comment expressed that the na passive filters tend to smooth/dull the sound of the streamed content subtly

i prefer the etherregen (and outboard clock) to handle the incoming ethernet feed personally, it is what i settled on after trying the eno and muon... it is more boxes and power supplies and so on, but to my ear the sound is purer

I did a lot of optimizations (tweaking for some) in my digital stack. Placing a Network Acoustics Muon Pro Ethernet filter and cable (Streaming Pro) has yielded a much more organic and less shouty (harsh) sound.

DAC’s do not like it when high frequency noise is injected via USB / Ethernet or the power grid (use a very good power cable).

I cannot recommend the Streaming Pro high enough…

But, a very low noise music server is the source, that should be noise free to begin with.

i prefer the etherregen (and outboard clock) to handle the incoming ethernet feed personally, it is what i settled on after trying the eno and muon... it is more boxes and power supplies and so on, but to my ear the sound is purer

Placing a Network Acoustics Muon Pro Ethernet filter and cable (Streaming Pro) has yielded a much more organic and less shouty (harsh) sound.....I cannot recommend the Streaming Pro high enough…

2 equally valid yet contrasting options, which suggests one must try on their own to find out if it works in ones system. I like the first answer though, that helps me to put the Muon lower on the "things to try list" that resides in my head. 

Like others have mentioned though, I don't think a software update should change your presentation that radically; the first thing I would do is research other forums to see if others with the ZENith mk3 have experienced the same? 

@bluethinker is this still your system?

• Innuos Zenith streamer with NRG “the five” cable
• Merason DAC1 with a LessLoss power cable
• Linear Tube Audio preamp with a cardas clear reflection cable
• Conrad Johnson Classic 120 with a Cardas Clear Beyond XL cable
• Speakers - switch between Dynaudio Heritage Specials and QLN Prestige 3

Is the digital glare evident with both sets of speakers?

If you had rebooted all your network and streaming components and it didn’t help, I would start with replacing the aftermarket power cords on streamer and DAC. Put the stock cables back on, allow it an hour to settle then listen. If the the digital glare is gone or reduced, introduce the aftermarket power cords one by one. See if that’s the problem.

What ICs and speaker cables are you using?