Update guaranteed-scheduling-critical-addon-pods.md (kubernetes#17151)

* Update guaranteed-scheduling-critical-addon-pods.md

cleanup old stuff again

* Update content/en/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods.md

Co-Authored-By: Tim Bannister <[email protected]>

* Update guaranteed-scheduling-critical-addon-pods.md

remove whitespace

content/en/docs/tasks/administer-cluster/guaranteed-scheduling-critical-addon-pods.md

@@ -27,10 +27,6 @@ For static pods, this means it can't be evicted, but for non-static pods, it jus
 
 ### Marking pod as critical
 
-Prior to v1.11, critical pod has to run in the `kube-system` namespace, this restriction was removed after v1.11 and pod in any namespace can be configed as a critical pod by the following either way:
-
-* Ensure the PodPriority [feature gates](/docs/reference/command-line-tools-reference/feature-gates/) is enabled. Have the priorityClassName set as "system-cluster-critical" or "system-node-critical", the latter being the highest for entire cluster, the two priority class names available since v1.10+
-
-* Alternatively, ensure both PodPriority and ExperimentalCriticalPodAnnotation feature gates are enabled, you could add an annotation `scheduler.alpha.kubernetes.io/critical-pod` as key and empty string as value to your pod, but this annotation is deprecated as of version 1.13 and will be removed in a future release.
+To mark a Pod as critical, set priorityClassName for that Pod to `system-cluster-critical` or `system-node-critical`. `system-node-critical` is the highest available priority, even higher than `system-cluster-critical`.
 
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