It's a bit confusing but Business Central (13.0) have cumulative Update released.
MSDYN365BC – Spring Release is a complete separate Release (14.0).
Microsoft has released, Cumulative Update 05 & 06 for Microsoft Dynamics 365 Business Central on-premises and is available for download.
Continue Reading Saurav Dhyani’s Article on their blog
MSDYN365BC – Cumulative Update 05 & 06 released for Business Central on Prem (13.0).
MSDYN365BC, #BCCU05, #BCCU06, #CumulativeUpdate13.0, #Hotfix
Blog Syndicated with Saurav Dhyani’s Permission