According to multiple sources familiar with the project, Activision is currently working on a Spyro the Dragon Trilogy Remaster, which will be announced in March 2018 and released in Q3 2018.
The trilogy remaster will, much like the highly successful Crash Bandicoot N. Sane Trilogy, feature new assets, lighting, animations and cinematics, as well as a remastered soundtrack. It will also feature updates to the save feature, much like occurred in the Crash remaster (which replaced the original games' password feature with something much more user friendly). The remaster will include Spyro the Dragon, Ripto's Rage!, and Year of the Dragon, and there is the tantalising promise of some content cut from the original releases of those games.
The Spyro remaster will be announced for PS4, with PS4 Pro support, sometime in March 2018, and will be releasing in Q3 2018. One source suggested that September would be the launch month, which would be in line with Spyro the Dragon's 20th anniversary.
While this detail will not be part of the announcement in March, the game will be a one-year timed exclusive for PS4, before being ported to other systems in 2019. Apparently, the Crash Bandicoot N. Sane Trilogy is tied to similar one year exclusivity window, so expect to see multiple ports of that in 2018.
Spyro the Dragon Trilogy Remastered is currently under development by Vicarious Visions, the same studio who handled Crash Bandicoot N.Sane Trilogy. Given the bandicoot's success, this release makes a lot of sense – soon enough we'll see whether the dinky purple dragon is remembered quite as fondly.