I would like to check out the early builds of the game again at some point. The last time I did this (.70b3) the contents of my mailbox disappeared even tho I started a new game and didn't touch the mailbox.  Would it be safer to bring all the items to my current 0.9C save before going back? If I lose my plushies again its no big deal. It'll just give me something to do and stay outside the base more. Right now I wanna see what happens when a save is brought to the 999th day while running at 2X day speed. No spoilers, please.

Backup your save, put the backup file somewhere outside of your votv folder, dont put anything in mailbox. Dont touch your save in the newer version, and then explore in old versions! If anything goes wrong, just put the backip back in your saves folder.