Settlement letter for an account that’s no longer reported

Today, I received mail from a law firm that purchased an old personal loan that’s no longer on my credit report.

History:

• Loan was from 2011, and went into collections in 2013. I settled in court in Nov 2014.
• However the collection agency I settled with shortly went out of business in Mar 2015, leaving me with no effective way to contact or repay (in fact, I received a check from my state’s comptroller for payments returned for this specific account)
• Debt was re-purchased by this (new) firm sometime between 2018 - 2019
• No reports from the new agency have landed on my report (My FICO) since the original debt purchaser (and judgement) fell off my report last year.

Just wondering if I should try to re-settle with this new firm, or, am I safe to ignore?