I have much to do with digital releases. I’m often not sure what kind of ranges are correct.
I have a digital album release postet and streamed on bandcamp. One of the tracks is also “released” as video on Youtube through a unplugged session for a radio station. Is that video a release? I read the documentation - but for me it is not totally clear.
UPDATE: Assumed both are releases, how are this both connected?
The Bandcamp release is a release. The YouTube video is probably a standalone recording (so “just” a recording without a release).
Both can be releases.
A recording is done when an artist records a song, resulting in some sort of final, to be published audio data. If an artist releases a song on two albums, but re-records the song for the second, it is a different recording. In your case, an »unplugged version« is (probably) very different to the studio recording, therefore it would be a different recording.
If the youtube video contains an actual music video or live performance (not just a still image), mark the youtube recording as a video.
(https://musicbrainz.org/doc/Recording)
The cleanest way is creating works for the tracks, or at least for the track that has two versions. Use the »recording of« relationship to link both versions to the work. That way, metadata like the composer and lyricist is shared between both recordings.
I’m quite a bit more inclusive than others here in what I consider comprising a release for digital (YouTube/Soundcloud) artists. In this case, I’d probably add a single for the “unplugged” release if it’s the only place that version appears. In general, my rule of thumb is that if something is on a song-sharing site (as opposed to Bandcamp’s album focus) as “from our new album” or is presented as a music/lyric video, I’ll add the link to the track or the standalone video recording, respectively, but not create a release; on the other hand, if that is the primary way the artist distributes their music – uploading each track as they finish and especially if they rarely, if ever, compile them into albums – I will create many Single releases. As @luziferius said, the “unplugged” version is almost certainly a separate recording, and if that radio station’s series is anything like the “X Sessions” I’m familiar with, that’s practically the only place to find that version – I’d call it enough for a single.
As for how each are connected, you have a couple options depending on the exact nature of each. If they actually have the same sound and the “video” is just a still image, they can use the same recording. If only the former is true (ignoring sound effects), the video recording can be linked to the audio with the “music video” relationship. If they sound distinctly different, however, the recordings shouldn’t be linked directly, and instead should just be given either the same work, or two works linked via a “based on” relationship.
Related discussion:
I am one of those less-inclusive editors (but my opinion means zilch, as I am still learning the site)…
I would think that a stream that isn’t archived (watch it live or never see it) would be more like an event than a release.
I would also wonder how, in the age of cell phones, would 200 people in an audience recording/posting the same song (from the same band from the same night) be considered. Is it a release or a event or a “don’t waste our time”.
Ok I think in most times the difference is clear. A release probably should anyway “come” from the artist (a fan video is not a release that is clear, also a fan recording of a live gig can’t be a release).
The existence of any cover work could a good hint for a release (but a unique soundcloud upload (from the artist directly in best way) is probably a release even there is no cover work -> some soundcloud artists do it only this way).
Here is my case. This is the original digital album audio track: https://www.youtube.com/watch?v=tsadyjqEeHw And this is the second recording/release https://www.youtube.com/watch?v=BbylBf1dm44
The recording of the radio station is also mixed and mastered. And I think it is the better version. Clearer voices and is better performed. The radio station session is also recorded without a banjo. On the albums original there is that third instrument.
But all in all now I think the radio station version isn’t really a release. It’s “only” a recording… I think 
It would be 200+ standalone recordings that would all be recorded at the given event. I wouldn’t make releases for them by default.