While the original Dumbo was a G-rated affair, it seems quite difficult to secure that rating these days.
Although, the live-action 101 Dalmatians remake from 1996 did manage it so it’s possible we could see a movie suitable for even the youngest viewers.
What Is Dumbo Rated?
It’s hard to imagine what could be added to Dumbo that might make it unsuitable for young kids, though the original movie did include an elephant getting drunk, which probably gets you at least a PG-rating today.