Rumored that the fountain lifts will be replaced with new ones (not going to require the RoA to be drained) and just regular TLC (speakers refurbed, lighting etc.). The show is MEANT to have downtime. Its only been running year round the past few years due to main street repave project taking away parades and other projects taking entertainment away which Disney went with running F! to make up for the gaps.
I'm so glad that it'll be coming back early March--in time for my trip at the end of that month. I haven't seen Fantasmic! in so long, so I'm excited to see it again in better condition than I'd seen it before.