About display of assets after version upgrade

I have upgraded from Ver0.9.9 to Ver0.9.11.
However, the assets placed on the level in Ver0.9.9 are not displayed on the level in Ver0.9.11.
There seems to be some assets deleted in Ver0.9.11.
Right now I’m working on copying the hidden assets to a new folder, but it’s taking too long.
Is there any other way?