Add 1.17 upgrade-specific note for upstream normalization. (#19181)

Add 1.17 upgrade-specific note for upstream normalization.

Co-authored-by: trujillo-adam <47586768+trujillo-adam@users.noreply.github.com>
Co-authored-by: Jeff Boruszak <104028618+boruszak@users.noreply.github.com>

website/content/docs/upgrading/upgrade-specific.mdx

@@ -19,6 +19,14 @@ upgrade flow.
 Prior to Consul 1.17.0, audit logs contained timestamps on both the original log file names as well as rotated log file names.
 After Consul 1.17.0, only timestamps will be included in rotated log file names.
 
+#### Service-defaults upstream config (Enterprise)
+Prior to Consul v1.17.0, [Kubernetes annotations for upstream services](/consul/docs/k8s/annotations-and-labels#consul-hashicorp-com-connect-service-upstreams)
+that did not explicitly specify a namespace or partition incorrectly used service-defaults configurations, such as [default protocol](https://developer.hashicorp.com/consul/docs/connect/config-entries/service-defaults#set-the-default-protocol), from the default partition and namespace instead of the local partition and namespace.
+
+This bug is fixed starting in Consul v1.17.0. Now service-defaults configurations from the local partition and namespace are fetched when not specified in annotations.
+If you are using non-default partitions and namespaces with Consul-k8s, we recommend explicitly defining these fields for all upstreams in addition to ensuring that accurate
+service-defaults are configured in each partition and namespace before upgrading. Doing so ensures that no unexpected protocol changes occur during the upgrade.
+
 ## Consul 1.16.x
 
 ### Known issues