Yes, it’s been released since 24.10.
The only storage layouts that can be expanded are raidzx (x= 1,2 or 3) but not mirrors
But there is still a drawback to raidz expansion which is discussed at length here
TLDR (as i understood it) the data written after expansion gets written with a different parity ratio then the old data was written with, which leads to a falsly displayed available space.
