diff --git a/netmap/marshal.go b/netmap/marshal.go
index f707665..47a2138 100644
--- a/netmap/marshal.go
+++ b/netmap/marshal.go
@@ -26,6 +26,7 @@ const (
 	backupPolicyField    = 2
 	selectorsPolicyField = 3
 	filtersPolicyField   = 4
+	uniquePolicyField    = 5
 
 	keyAttributeField     = 1
 	valueAttributeField   = 2
@@ -166,6 +167,8 @@ func (p *PlacementPolicy) StableMarshal(buf []byte) []byte {
 		offset += protoutil.NestedStructureMarshal(filtersPolicyField, buf[offset:], &p.filters[i])
 	}
 
+	offset += protoutil.BoolMarshal(uniquePolicyField, buf[offset:], p.unique)
+
 	return buf
 }
 
diff --git a/netmap/types.go b/netmap/types.go
index aece7cf..bda9ec6 100644
--- a/netmap/types.go
+++ b/netmap/types.go
@@ -55,11 +55,11 @@ type Replica struct {
 type Operation uint32
 
 type PlacementPolicy struct {
-	unique       bool
 	replicas     []Replica
 	backupFactor uint32
 	selectors    []Selector
 	filters      []Filter
+	unique       bool
 }
 
 // Attribute of storage node.