Proved and proven

Which is correct: ‘That hasn’t been proved’, or ‘That hasn’t been proven’?

What are the rules for using ‘proved’/‘proven’?

That hasn’t been proven, because nobody proved it.

Actually, both are correct. The past participle for “prove” is either “proven” or “proved.”

And a cite:

The past tense is always “proved”: “The defense attorney proved his client could not have been at the scene of the crime.” As noted, both terms are in use as the past participle.

‘Proven’ is obsolete usage, except in Scottish courts which can return a “not proven” verdict.

‘Unproven’ and ‘Disproven’ remain in current usage.

I hear “proven” often enough used as a past participle. I hardly think it’s obsolete. The citation I provided above seems to agree.