Raspberries

Please forgiven me if this particular topic has been previously raised and answered!!

I've recently taken over a new plot. There is a fruit area. Growing Raspberry canes are in evidence. Today, finally, I've been informed these raspberries are of the autumn fruiting type. There certainly is plenty of new growth for this year's crop. But, because last year's canes are still standing and it appears producing new growth. Is it advisable to cut the old canes out and rely on this year's growth only? Or leave both old canes and new growth and crop from both? Will the old canes crop? Or just take-up space and produce nothing in the end? At least now I know the correct pruning procedure to follow. Thanks.   

Leave the old cane's and you will get fruit on both them and the new cane's. It is advisable though to cut all the cane's down to about 4ins in the winter.