I’d offer a one year contract with an option for another year, with the view to being more squad player than guaranteed first teameas time progresses (as previously suggested). Although I’d love to be more sentimental, we can’t afford to be.
I’m not saying he’s no longer an asset. If that was the case, then it’s thanks for the memories and goodbye.
One objective way (although doesn’t take into account squad experience) is to think would the likes of Hull, Peterborough, Sunderland, Huddersfield, Rotherham, Shef Wed, Derby or Forest want to sign him next year? These are all teams likely to be bottom half Championship or promotion hopefuls in L1. There isn’t an obvious answer for me, but maybe not. As it’s worked well so far - keep going unless we can sign obviously better players on similar money for next season (pretty unlikely).