"Forgotten" or "forgot" as past participle of "forget"

In US and in UK respectively, which is more popular as the past participle of forget: forgotten or forgot? Which is more formal/informal?

Examples:

I haven't forgot(ten) you.

You will not be forgot(ten).

Solution 1:

The OED describes the use of the past participle forgot as 'archaic' and 'poetical'.

Solution 2:

Grammatically speaking I don't really think haven't forgot is a cardinal sin compared to some usages that make it into popular parlance, but it does seem that people mostly get this one right.

Solution 3:

Honestly speaking, as an educated southerner and an ESL instructor, I needed to look up the past participle of this word one more time. I interchange between the two without noticing. Sometimes I say, "I have forgot my keys." Sometimes I say, "She's forgotten her money." I would say both are accepted as past participle forms in the Appalachian region and southeastern United States. I heard my doctor say, "You haven't forgot what I told you, have ya?" He has a degree in medicine from Emory University. In my informal speech I often use words that the British stopped using hundreds of years ago. My ancestors wanted to keep a piece of the motherland (Great Britain) so they made a conscious effort to use words and phrases such as "gotten" and "yonder."