If they've finished fruiting completely, they should be summer fruiting raspberries. The canes will look woody and brown, and the leaves will be yellowing. There should also be new growth, fresh green canes, with fresh green leaves. Cut down only the old canes, right to the ground. Do it now. Leave any new growth that is already there or that grows. These are the canes which will fruit next year.
For raspberries which are still fruiting, which will be late varieties, cut down in October, right to the ground - I leave one or two showing only - these will produce fresh growth next spring which will fruit nex autumn.