ISO 9001:2015 is the latest version that launched since September 2015 to replace the ISO 9001:2008. Many of the existing certified organization is working to upgrade their ISO 9001 system to this latest 2015 version.
ISO organization are given the buffer time that the organization are able to upgrade their ISO 9001 before September 2018. After September 2018, all ISO 9001:2008 version certificate are no longer valid.
The major changes in the new version are the structure. ISO 9001:2015 are follow the same structure as other ISO management system. It is easier for the organization to do the integration with the other ISO system.