According to a press release on FuntownSplashTownUSA.com, the Astrosphere is getting a significant update for 2019.

The biggest part will be switching from an "airform" dome to a concrete dome.  The current dome, in place for the last 43 seasons, has been constantly inflated by a fan.  As a result, it is nearing the end of its lifespan.

Because it will be easier to control the temperature inside, the concrete dome will provide riders with a much better experience.  No more sweating buckets on the hottest days!  On top of that, workers will no longer have to assemble the dome at the beginning of each season (and disassemble it at the end of the season).

There'll also be updates to the laser and effect show during the ride.

Good news for long-time fans of the ride, the song will not change.  The EPIC track playing during the ride will continue to be ELO's "Fire On High"