The rolling system updates occur each April. For example, April 2019 will see it update to pre-1979 vehicles and so on. To reclassify car as an Historic Vehicle, go to Section 7 of your V5C and complete the Tax Class section, altering it to ‘historic’. Then sign and date the bottom of that page and take your V5C along to a VED-issuing Post Office, complete with a completed V10 car tax application form and your MoT certificate. The Post Office will issue your car tax free of charge (as a Historic Vehicle) and will send your V5C to the DVLA. You’ll then receive a replacement V5C in the post, plus a cheque for any unexpired (previously paid for) VED.