Back in September the United Kingdom released a new polymer-plastic 5 pound note into circulation. The new bills are more secure and durable than the old cotton paper bills.
Starting on May 17, 2017, the old paper 5 pound notes will no longer be accepted by merchants. If you still have the old bills you can still exchange them for the new ones at any Bank of England. The new plastic 10 pound notes will be released in the summer of 2017 and the 20 pound notes will follow by 2020.
Australia has also released a new polymer AUD5 note in September. Their bills have raised dots to assist the blind.