Guitar Hero Live's GHTV mode, which offered live shows to play along with, is shutting down in December.
GHTV offered a series of curated music videos and concerts you could tune in to and play along with. It offered an experience unlike anything else available at the time, evoking a classic MTV-like feeling with different "channels" and genres to explore rather than selecting songs from a setlist on demand.
The game mode will still be functional for the console versions of the game, but you won't be able to purchase any new shows from June 1 onward. You can continue to utilize Hero Cash and any items you already had until the December shutdown, if that's any consolation, however.
Additionally iOS versions of Guitar Hero Live are being yanked from the App Store on June 1. So if you want to keep it around you might want to make sure you have it downloaded and installed on a device you won't continue to update. As soon as you do so, it could cease to work in the future.
Unfortunately, this is another nail in the coffin for the Guitar Hero series, which hasn't been able to stay relevant like Rock Band 4 has. It's been operational, however, for the past three years, so perhaps it's had a good run. We likely won't see another entry in the long-running music franchise, so it might truly be time to say goodbye now.