Is extending RAIDZ volumes coming soon?

Hey all, I read that ZFS has added the ability to extend/grow volumes in recent months. Is the ability to grow a RAIDZ volume in FreeNAS on the road map? I would love to be able to grow my current three disk RAIDZ to four, by just adding an additional disk of the same size. Just curious if this is coming soon, or if I've misunderstood and this is still technical limitation in ZFS.

Thanks for everything you guys do, I've been a FreeNAS fanatic for many years!