I've seen several posts from prospective 2016 and 2017 model owners believing you must purchase HEOS (Wifi/Bluetooth) speakers in order to take advantage of the built-in HEOS module in the Denon "H" series models, which is not entirely correct. There are two ways to take advantage of the built-in HEOS module:
(1) Use the HEOS app (iOS/Android; Free) to stream currently one of 14 different music services to the AVR (Pandora, Spotify, TuneIn, Amazon Music, DEEZER, Napster, iHeartRadio, SiriusXM, SOUNDCLOUD, TIDAL, Rhapsody, JUKE!, AWA, QPlay). Note unlike on non-HEOS models, the music services are no longer on board the AVR, but rather the app is used initially, and then the stream can be saved as a HEOS Favorite so the app is no longer required for that particular stream.
(2) Stream 2CH music sources to from 1 - 32 HEOS speakers set up around the home with the same limitation as passing Zone 2 sources for that particular model. You can effectively have 32 independent zones or can group up to 16 HEOS speakers for the same "whole house" audio. Additionally, 2 same model speakers can be configured as STEREO Left/Right.
Additionally, with a soon to be released firmware update to the "H" models, the Echo and Echo Dot (ie. products with Alexa) will be able to control the AVR and HEOS HS2 (version 2 only) speaker functionality using voice commands to Alexa.