Kernel Os 1809 13 ((full)) -

: Switching the default system timer to TSC (Time Stamp Counter) and disabling the Fault Tolerant Heap to reduce processing delays.

Extended support for the 1809-based LTSC version continues until January 9, 2029 ITonDemand Critical Security & Kernel Notes MDS Mitigations : If managing 1809 on older hardware, refer to ADV 190013 kernel os 1809 13

Build 17763.13 introduced early support for: : Switching the default system timer to TSC

The 17763 kernel version is canonical for 1809. But the number 13 most likely refers to a applied to that kernel. For instance: kernel os 1809 13

When you see "kernel os 1809 13," you are looking at a specific patch level. Build 17763.13 was released in as part of KB4467708 .