Enable decay after a week - What would happen?

Well I noticed that the world still has floating blocks and stuff cause the decay wasn't working, I checked the config and sure enough it was off by default.

Now that it's been like a week or more since the update what would happen to bases over 4 days old if I turned on the decay? would crest go from then to 4 days or would bases begin disappearing?

 

When you did no wipe after the last update you have to wipe for sure to have the old crests/blocks decay.

 

we had full wipe, just didn't know the decay was off when we started it back. But what will happen to the crests that have been made on the day of the update? (over 4 days old) Would they disappear since the decay for to happen after 4 days

 

I guess they will just be empty so as long as they refill the crests with wood nothing will decay.