diff --git a/cloud/docs/orca-relay-operations.md b/cloud/docs/orca-relay-operations.md
index f27b437fff9..4515048b29b 100644
--- a/cloud/docs/orca-relay-operations.md
+++ b/cloud/docs/orca-relay-operations.md
@@ -466,11 +466,16 @@ After a deployment traffic shift, preserve the old revision/tag until metrics an
 
 ## Regional rehoming
 
-Rehoming moves a host to a general cell in the region its desktop last reported, in either
-direction. Both roles need the drain protocol: a cell without it can be neither a source nor a
-target, and it is not part of the fleet whose telemetry gates the worker. Until the asia-east2
-cells run `regionalRehomeProtocol` 1 they are none of the three, so no host is moved into or out
-of Asia and an Asia cell in distress does not pause the worker.
+Idle regional correction requires both source and target cells to advertise
+`regionalRehomeProtocol >= 3`. PR #20105 introduced this capability version with
+the idle handoff implementation. With that runtime, both rehome trust environment
+settings must be configured to advertise 3; otherwise the cell advertises 0.
+An older trusted runtime can advertise 1: configuring trust alone does not upgrade
+its implementation. The separate `connectionCapacityProtocol: 2` health field does
+not establish regional-correction readiness. Verify the live runtime version and
+image, not only instance-template configuration, before rollout or enablement.
+Incompatible cells are excluded from correction selection; enabling the cohort
+cannot override this check. Director and cell deployments are separate operations.
 
 `host-cooldown-ms` is the minimum gap between two rehomes of one host. It bounds the damage from
 a desktop whose region probe flips: without it the host would be dragged back across the ocean on