Old UK Royal mail stamps - time running out for the old versions to be converted to Barcoded versions

In February 2022 new barcoded "definitive design" stamps were introduced. The rectangular (matrix) codes, unique to each stamp, use a trademarked coding designed to prevent counterfeiting and to enable tracking of letters, and to enable correspondents to link digital content to their stamps. Until 2022 any 1st and 2nd class and decimal currency postage stamps could be used; old Machin and country definitive design stamps without barcodes are no longer valid from 31st July 2023, with old ones exchangeable for barcoded ones indefinitely through a process which Royal Mail calls the "Stamp Swap Out scheme". Special Stamps with pictures and Christmas Stamps without a barcode continued to be valid Stamps are exchanged like-for-like: a "1st class" stamp will be replaced by a 1st class one, not 95p.