Question [Q] Galaxy S2 I9100xxlq5 4.1 offical

Hi

I am looking for upgrading my Galaxy S2 I9100XXLQ5 currently on 4.0.4 official to official 4.1.X. But I am not able to find official ROM matching my baseband. Please confirm where i can find matching baseband ROM, and if we load unmatching rom does it has any issues????

Thanks