I own a 2019, a 2017, and multiple 2015 shields. I can confirm that they will all properly bitstream lossless DTS-HD-MA and Dolby TrueHD via Plex, Kodi, and SPMC, for both 1:1 1080p Blu Ray MKV rips, and 1:1 4K UHD Blu Ray MKV Rips.
Plex is pretty plug-n-play simple, far less customizable, but requires a "server-side-device" to be running (although the Shield is capable of being both server and client, if you want). Kodi and SPMC take a bit more elbow grease/wading through menus/configuring to get up and running, but tend to be far more customizable if you choose to...
Living Room: Sony x940E; Denon x4400h; Ascend Sierra RAAL Tower L/R's and 2EX center, Ascend HTM-200SE Rears, Rythmik F25 sub. NVidia Shield, ATV4k, OPPO UDP-203, CCA.
Basement: Samsung PN58B650 & LN-T4065F (x2); Onkyo TX-NR809; Polk Monitor 70 Series II L/R's, SVS PB-1000 sub. NVidia Shield (x2), Windows Desktop, CCA, Pi running Ropieee.