Or if they really need so many minor version numbers before the first stable release, they could do the odd-even thing, where odd major versions are devel and e

Or if they really need so many minor version numbers before the first stable release, they could do the odd-even thing, where odd major versions are devel and even major versions are stable. So skip to 5.x for the next development cycle, then bump to 6.0 when the API becomes stable. Then 7.x for devel, 8.0 for stable, etc.