Used wrong year 1040-V printed coupon
I just mailed my payment due for my 2021 tax return (I filed electronically and the return was accepted before I mailed the payment) and realized that I used the 1040-V coupon that had "2020" on it. That coupon was with the 2021 1040-ES quarterly coupons the IRS sent me and I used it instead of the new one. I believe I noted on the check that the payment was for 2021 Form 1040-V and the exact amount matches my balance due from my 2021 Form 1040. Should I be concerned about this or will the IRS properly apply my payment to my 2021 balance due? I don't owe a balance for 2020.