How latest the sponsor's bank letter should be for sponsoring a vistor visa

[masood4all]

Hello
I have had requested a copy of the Bank letter around 6 months back to sponsor visitor visa for my Parents. However due to some constraints the visa processing couldn't complete. Now that all my sponsor papers are ready i'm wondering if i can have my parents carry the old Bank letter or i should request a latest Bank letter and send it to them

Thanks

[immihelp]

Send again.