diff --git a/control/controlclient/map.go b/control/controlclient/map.go
index 9f0e706cd..df2182c8b 100644
--- a/control/controlclient/map.go
+++ b/control/controlclient/map.go
@@ -89,7 +89,6 @@ type mapSession struct {
 	lastPopBrowserURL      string
 	lastTKAInfo            *tailcfg.TKAInfo
 	lastNetmapSummary      string // from NetworkMap.VeryConcise
-	lastMaxExpiry          time.Duration
 }
 
 // newMapSession returns a mostly unconfigured new mapSession.
@@ -384,9 +383,6 @@ func (ms *mapSession) updateStateFromResponse(resp *tailcfg.MapResponse) {
 	if resp.TKAInfo != nil {
 		ms.lastTKAInfo = resp.TKAInfo
 	}
-	if resp.MaxKeyDuration > 0 {
-		ms.lastMaxExpiry = resp.MaxKeyDuration
-	}
 }
 
 var (
@@ -819,7 +815,6 @@ func (ms *mapSession) netmap() *netmap.NetworkMap {
 		DERPMap:           ms.lastDERPMap,
 		ControlHealth:     ms.lastHealth,
 		TKAEnabled:        ms.lastTKAInfo != nil && !ms.lastTKAInfo.Disabled,
-		MaxKeyDuration:    ms.lastMaxExpiry,
 	}
 
 	if ms.lastTKAInfo != nil && ms.lastTKAInfo.Head != "" {
diff --git a/tailcfg/tailcfg.go b/tailcfg/tailcfg.go
index 7038d8adc..4d30f6501 100644
--- a/tailcfg/tailcfg.go
+++ b/tailcfg/tailcfg.go
@@ -2022,10 +2022,6 @@ type MapResponse struct {
 	// auto-update setting doesn't change if the tailnet admin flips the
 	// default after the node registered.
 	DefaultAutoUpdate opt.Bool `json:",omitempty"`
-
-	// MaxKeyDuration describes the MaxKeyDuration setting for the tailnet.
-	// If zero, the value is unchanged.
-	MaxKeyDuration time.Duration `json:",omitempty"`
 }
 
 // ClientVersion is information about the latest client version that's available
diff --git a/types/netmap/netmap.go b/types/netmap/netmap.go
index 94db7a477..b1eecaa8f 100644
--- a/types/netmap/netmap.go
+++ b/types/netmap/netmap.go
@@ -79,9 +79,6 @@ type NetworkMap struct {
 	// UserProfiles contains the profile information of UserIDs referenced
 	// in SelfNode and Peers.
 	UserProfiles map[tailcfg.UserID]tailcfg.UserProfileView
-
-	// MaxKeyDuration describes the MaxKeyDuration setting for the tailnet.
-	MaxKeyDuration time.Duration
 }
 
 // User returns nm.SelfNode.User if nm.SelfNode is non-nil, otherwise it returns
diff --git a/types/netmap/nodemut.go b/types/netmap/nodemut.go
index 6f116059e..e31c731be 100644
--- a/types/netmap/nodemut.go
+++ b/types/netmap/nodemut.go
@@ -176,6 +176,5 @@ func mapResponseContainsNonPatchFields(res *tailcfg.MapResponse) bool {
 		// function is called, so it should never be set anyway. But for
 		// completedness, and for tests, check it too:
 		res.PeersChanged != nil ||
-		res.DefaultAutoUpdate != "" ||
-		res.MaxKeyDuration > 0
+		res.DefaultAutoUpdate != ""
 }