Cumulative Update 4 for Microsoft Dynamics NAV 2015 has been released today. It includes almost all application (Administration, Client, Finance, FA, Inventory, Jobs, Manufacturing, Purchase, Sales, Server, Service and Warehouse) and platform hotfixes and regulatory features that have been for Microsoft Dynamics NAV 2015. It also has a lot hotfixes for following localisations: Australia, Spanish, Italy, France, North America, Netherlands, Russia, Sweden, United Kingdom.
You can download Cumulative Update 4 for Microsoft Dynamics NAV 2015 from here. This CU is named as Build 39663.