[capableweb]

Yes, if I understand IPFS correctly, you can. Since IPFS works as a content addressed system, if you embed the date, send the document to the judge (the hash which is based on the content), don't show it until a later point, you can prove the document is the same as you sent, even without revealing the content until later.

IPFS doesn't seem to have anything about "version control" as onyb mentioned.

[tingletech]

what prevents me from pre-dating a document on IPFS?

[bluesign]

how you will embed the date?

[jstanley]

The IPFS hash is a hash of the content. Simply including the date as text would suffice.

[lmm]

What stops you from backdating a document when you write it?

[jstanley]

Nothing. Including the date doesn't do anything other than commit yourself to stating that date, the important part is the date at which you commit to the hash.

[capableweb]

I'm assuming to you add the document (with date) to IPFS without being connected to the network (no actual data gets shared, only hash), gets the hash and send it over to the person you need to prove the document's date to. They won't be able to get it (since content itself is offline) and once you want to prove it, you add it again or make it otherwise online. Then they can fetch the same hash and confirm they received the hash at the date.