Hi,
OK, here's a more detailed review of the Fiio R7 after spending some time with it.
I will not get over features again as I think those have all been discussed already, but will report about my experience after several hours.
First thing : I'd like to remember that what I wanted to achieve with this device was following :
- being able to attach a USB Stick to it and be able to browse the content of that USB Stick remotely ;
- being able to use the device as a renderer so I can take the files from the USB stick and play them on the R7 ;
- of being able to do all that remotely from my smartphone.
Can I do this ?
For sure it seems I can not do that with Fiio software.
In Fiio 3.2 I have enabled the "lab" features and especially the "Transmission over DLNA" and the "Receiving over DLNA" fetures.
By doing so, I hoped that I could see the files from my smartphone and browse the files through my smartphone.
Well, I can't do that, unfortunately...
Despite enabling those features, the R7 content does not show up in apps on my phone which include : Fiio, BubbleUPnP, mConnect, MediaMonkey, HiBy, Hi-Fi Cast, Eddict player, UAPP and Neutron.
So I assume it simply can't be used as a DLNA server.
So long for this part...
That is already a huge disappointment...
OK, it seems I can't use the R7 as a media server, unless I install something else on it.
So I installed UAPP and scanned my entire library.
Takes a while...
Once done, I enabled UPnP renderer on UAPP and there we go : it now looks like like I can browse through files on the R7.
So now, can I use it as a renderer ?
- With the Fiio app : absolutely not.
Why ? Because Fiio displays tracks alphabetically ! No, no kiddin'. I open the Fiio App on my smartphone. I go to the UAPP R7 server. I am presented with a choice of browsing files by artist, tracks or by Folders. Let's take folders. I browse to the desired folder and open it's content => files alphabetically shown. OK. Maybe if I browse by artist ? Same result. OK. Maybe it's a problem with my tracks naming in the folder. So let's try several folders... Nope, not working. All by alphabetical order. Wait... Maybe it is the way UAPP sorts the files... Let's check with another app. Let's go for, say, A&K app. Browsing through folders => track number. OK. Problem solved : it is Fiio app so that is basically useless (unless of course there is a setting I haven't discovered, but ergonomics is not the best part of Fiio App).
- With A&K app : let's try A&K app. I can detect UAPP Server so can play files from the R7 USB Stick, even if not over the Fiio app.
It can stream to the R7 used as a renderer. Let's see... OK. Streaming to Fiio music => not working. Fiio Music detects a signal because the display "blinks". But playback does not start.
So let's try to stream to UAPP. Playback starts. But will it play several tracks in a row and gapless ? Let's try with Pink Floyd DSOTM Live in Wembley... OK. It jumps to next track but there is a small gap

Maybe a fraction of a second, but still...
Anyways, so far, R7 is not a solution that works on it's own. It needs the assistance of third party software.
- WithBubble UPnP :
I usually disable the FFMPeg reformatting of files. But if I do that and try to send files to R7 over Fiio app BubbleUPnp says "No compatible decoder was found". What ? I am sending a .flac file ! Fiio as a renderer does not support .flac ? OK. Let's enable FFMEG transcoding. Now file is played by Fiio app on the R7. But first thing : it does not display cover art. But OK, that might be caused by the fact that UAPP does not send metadata nicely. It works... But nice 1 second gap between tracks. Not what I am looking for
What if I stream to UAPP enabled as a renderer ? Works without FFMPEG transcoding. Good. That may preserve my battery life on smartphone. Still, no cover art. I had that with A&K... Weird

Let's see if it goes to next track and gapless... Yes, it does.
Anyways, so far, R7 is not a solution that works on it's own. It needs the assistance of third party software.
- With Eddict software :
For those not aware, Eddict software is the software used by Shanling. It can use NAS as source and so it can retrieve files from the R7 when UAPP is enabled as a server. It can also send files to DLNA and so it can be used to send files to the R7.
Sending files to the R7 to the Fiio app with renderer enabled : not working. Playback does simply not start.
Sending the files to UAPP does work. I get cover art. Now do I have gapless playback ? Fingers crossed... Not o,nly do I NOT have gapless playback, but playback stops after first track. So this is not a solution unfortunately
Anyways, so far, R7 is not a solution that works on it's own. It needs the assistance of third party software.
- With Hi-Fi Cast :
HiFi Cast can detect the UAPP R7 Server. But it is unable to retrieve files from UAPP Server. So that will be a really short report
-With mConnect :
mConnect can detect the UAPP library. So I browse through files and send the files to the R7 over Fiio app. Not working. It skips to next track after 1 second... So goes Fiio app. Looks more and more that Fiio is like Shanling : decent hardware but questionable software. I am saying this being aware that it is "experimental" and that maybe the cause is UAPP so I will of course try to see if I can have it in a different way.
What about same playing to UAPP as a renderer on the R7 ? Playback starts. I have cover art on the R7 (but not in mConnect). Let's see if it skips to necxt track and if it does so gapless... Yes. Skips to next track and gapless.
Anyways, so far, R7 is not a solution that works on it's own. It needs the assistance of third party software.
- With MediaMonkey
As usual : not working with Fiio R7 as a target. That is now an habit...
Working with UAPP though. I get cover art. Tracks play after each others. But small gap. About a fraction of a second but still really audible.
- With UAPP :
Ah... It is sending files to Fiio on R7 ! No, ust kiddin' of course. As all others, it does not send files to the R7 using Fiio app as a renderer.
But it does of course send files to UAPP as a renderer on the R7. And I get cover art. That is the least to expect ! After all am sending from UAPP to... UAPP

Will it skip to next track and do so gapless ? yes, as soon as you check the setting about gapless playback in the renderer settings.
- With Neutron :
Can't be used as a remote app. It can see the UAPP R7 as file server. But it does not detect any files in that DLNA server. So it basically can't play anything... But I will install it on the R7 and use it as a renderer.
I have tried to use a media server like Plex to serve files to the Fiio R7 app.
All that was NOT working when using UAPP as a media file server now works.
BUT : I want to have an all-in-one autonomous solution.
This requires an external computer to serve files
So if anyone can point out a way to browse through files stored on USB stick hooked into R7 I'm a taker and will test all the above but with something else than UAPP.
Regards.