Which version of IPBoard are relevant?

IPBoard, now known as Invision Community, has several relevant versions, with the most current being Invision Community 4.x, which introduced significant improvements in user experience, performance, and customization. Earlier versions like IPB 3.x are still used by some communities but lack the modern features and support found in the latest releases. It's essential for users to stay updated with the latest version to benefit from security patches, new functionalities, and ongoing support from the developers.