received unemployment letter maybe fraud ?

Probably.  Someone else probably applied using your identity.  Very common.

"Spock" is correct.  I would like to add that you should check all three credit reports for any unauthorized loans or credit card applications.

Scam, delete they want your bank details.

do NOT reply online or by telephone, EVER.  Seems that someone has stolen your identity for purposes of fraud.  Verify the address of the unemployment office in your area,  then, write back, including copy of the letter, to the verified address and tell them it looks like fraud because you're retired and have been for 11 years -- someone likely stole your identity.  You might/should also file a report with local police of stolen identity -- just in case some scammer out there tries to do something like use your identity to borrow money that a bank later wants you to repay.  AND, change all the passwords on all your online accounts.  PLUS, send copy of police report to every financial institution you deal with -- you want to forestall any attempt to impersonate you and get ahold of your assets.  -- GL  -- grampa  [I'm only 69 -- and everyone has to be vigilant about keeping any apparent fraudster out of their assets.]

Ignore it.  It is obviously an attempt to scam.  Let me guess, it offers a phone number to call?  When you make that call they will attempt to tell you a legitimate reason why they need your social security number.

Make sure the check was signed by Biden and not Trump !

Contact EDD................