Platform Update 15 for D365 FO On-premises is now ready to download from LCS. Please follow the steps outlined in the following documentation to apply the update:

https://docs.microsoft.com/en-us/dynamics365/unified-operations/dev-itpro/deployment/apply-updates-on-premises

Here is a description of what is included in PU15:

https://docs.microsoft.com/en-us/dynamics365/unified-operations/fin-and-ops/get-started/whats-new-platform-update-15

The binary update also includes several hotfixes which have been released after the initial PU15 release.