From WIKI
Gapless playback is the uninterrupted playback of consecutive audio tracks, such that relative time distances in the original audio source are preserved over track boundaries on playback. For this to be useful, other artifacts at track boundaries should not be severed either. Gapless playback is common with compact discs, gramophone records, or tapes, but is not always available with other formats that employ compressed digital audio. The absence of gapless playback is a source of annoyance to listeners of music where tracks are meant to segue into each other, such as some classical music, progressive rock, concept albums, electronic music, and live recordings with audience noise between tracks.
Wikipedia
The issue for some may be using compressed audio.
Im on my 3rd (DIY) streamer using Jriver in DNLA mode and no problems with Gapless playback
Technics 1200 tweaked,Ianmac Bearing,DACT DIY Phono Pre, Belcanto CD-2, Engineered Switzerland DIY Renderer, Benchmark DAC2, Hypex NCore, ATC SCM40
2nd system --Engineered Switzerland DIY streamer, Sony CDP11,Topping D50 DAC, Hypex NCore. Kef 1point2 speakers. Ianmac Filters