In October 2017, Microsoft announced that from Spring 2018 Microsoft Dynamics 365 for Finance and Operations, Business Edition would become the same product as Microsoft Dynamics NAV 2018 R2, just only in the cloud (and only with the web client). It was code-named Dynamics 365 'Tenerife'. The spring release would also become the last version carrying the Dynamics NAV name. Following the spring release, both the cloud and the on-premise version would be given the same name.
Going forward there would be two major releases per year - a spring and a fall release, and then CU updates on a monthly basis.
The first release named Microsoft Dynamics 365 Business Central was the Spring 2018 release, which was released on April 2nd. 2018.