Hi,
Please find more information about Cumulative Update for Microsoft Dynamics 365 Business Central/NAV released in April 2020 below.
Here you can find the download link.
Business Central Cumulative Updates
Cumulative Update 18 for Microsoft Dynamics 365 Business Central October’18 on-premises (Build 41909/41879)
Cumulative Update 11 for Microsoft Dynamics 365 Business Central April’19 on-premises (Build 41935/41862)
Cumulative Update 5 for Microsoft Dynamics 365 Business Central 2019 Release Wave 2 on-premises (Build 41926/41893)
NAV Cumulative Updates
Cumulative Update 28 for Microsoft Dynamics NAV 2018 has been released (Build 41920)
Cumulative Update 41 for Microsoft Dynamics NAV 2017 has been released (Build 30219)
Cumulative Update 54 for Microsoft Dynamics NAV 2016 has been released (Build 51811)