Plusnet allow you to renew your contract three months before its end date with no penalty. They will let you upgrade at any time during your contract but that will start a new contract. It is entirely up to you whether you avail yourself of any offer then or at anytime up to the end date. You are probably aware that you will move on to a rolling monthly contract after that date and will lose any discounts.
Plusnet will email you again before the end date - about one month from then if I recall correctly - but you do not need to await such emails. You can contact the Customer Options Team at any time to see what the best current deals are - 0800 013 2632 - and can decide whether to take one up or not. If you decide to take up a new contract it will usually start on the next day and will supersede your existing contract. Your billing date will remain the same and any discrepancies between prices in the old contract (which you will have paid in advance) and the new will be sorted out in the next bill ( possibly or two if you move contracts near the billing date).
