As a matter of fact, the news of the partnership of Sportsbet.io and Southampton FC is already a contract extension. They were already partners since last year. It's an old news. It was in August last year when The Saints welcomed Sportsbet.io as the main club partner.[3]
Cool! You provided really useful information. Even the OP doesn't know about this information, right? I thought it was the first time they signed, but with this contract extension it means Sportbet.io got what they wanted through contract. Well, I don't think it is wrong to accept sponsorship from casinos, as long as gambling is not prohibited in those countries.