The current version, v3.2.1, will be supported for another two years, until March 31st, 2024. This will provide relevant organizations with enough time to learn about version 4.0 and implement the changes.
In addition to the amended standard, the PCI SCC has released a number of supporting publications in the PCI SSC Document Library. The PCI DSS v3.2.1 to v4.0 Summary of Changes, the v4.0 Report on Compliance (ROC) Template, ROC Attestations of Compliance (AOC), and ROC Frequently Asked Questions are among them. In the next weeks, Self-Assessment Questionnaires (SAQs) will also be released.