As of 1 October 2018, the “Dynamics NAV” product has effectively been renamed “Dynamics 365 Business Central”. “Dynamics NAV 2018” is the last version of Dynamics NAV – it’s successor is “Dynamics 365 Business Central On Premise”.
The transition is as seamless as any regular Dynamics NAV upgrade. All existing Dynamics NAV customisations are still supported, and Microsoft will continue to support the “on premise” edition of the product.
This is similar to the experience with CRM – which Microsoft has supported for many years in both an on premise and cloud edition.
Further details from Microsoft : Explore Microsoft Dynamics 365 Business Central