So the patch notes for the new update indicated that they fixed withers spawning in the nether fortress. However, my world still does not.

My world was synced, added to a Realm, and has been on there ever since Minecraft's day of release. The nether fortress has remained empty ever since I synced the world. The new update did not spawn any withers in my fortress. In fact, the fortress is completely empty (including empty blaze spawners).

No i can not reverse the world 5 months and lose everything we got.