diff --git a/v2/container/convert.go b/v2/container/convert.go
index d40813f..386eb8e 100644
--- a/v2/container/convert.go
+++ b/v2/container/convert.go
@@ -857,6 +857,8 @@ func UsedSpaceAnnouncementToGRPCMessage(a *UsedSpaceAnnouncement) *container.Ann
 
 	m := new(container.AnnounceUsedSpaceRequest_Body_Announcement)
 
+	m.SetEpoch(a.GetEpoch())
+
 	m.SetContainerId(
 		refs.ContainerIDToGRPCMessage(a.GetContainerID()),
 	)
@@ -873,6 +875,8 @@ func UsedSpaceAnnouncementFromGRPCMessage(m *container.AnnounceUsedSpaceRequest_
 
 	a := new(UsedSpaceAnnouncement)
 
+	a.SetEpoch(m.GetEpoch())
+
 	a.SetContainerID(
 		refs.ContainerIDFromGRPCMessage(m.GetContainerId()),
 	)
diff --git a/v2/container/grpc/service.go b/v2/container/grpc/service.go
index 98c5cc6..644ca3a 100644
--- a/v2/container/grpc/service.go
+++ b/v2/container/grpc/service.go
@@ -354,6 +354,13 @@ func (m *GetExtendedACLResponse) SetVerifyHeader(v *session.ResponseVerification
 	}
 }
 
+// SetEpoch sets epoch of the size estimation.
+func (m *AnnounceUsedSpaceRequest_Body_Announcement) SetEpoch(v uint64) {
+	if m != nil {
+		m.Epoch = v
+	}
+}
+
 // SetContainerId sets identifier of the container.
 func (m *AnnounceUsedSpaceRequest_Body_Announcement) SetContainerId(v *refs.ContainerID) {
 	if m != nil {
diff --git a/v2/container/grpc/service.pb.go b/v2/container/grpc/service.pb.go
index 2951a95..88dbb48 100644
Binary files a/v2/container/grpc/service.pb.go and b/v2/container/grpc/service.pb.go differ
diff --git a/v2/container/marshal.go b/v2/container/marshal.go
index f86d964..ae190bd 100644
--- a/v2/container/marshal.go
+++ b/v2/container/marshal.go
@@ -41,8 +41,9 @@ const (
 	getEACLRespBodyTableField     = 1
 	getEACLRespBodySignatureField = 2
 
-	usedSpaceAnnounceCIDField       = 1
-	usedSpaceAnnounceUsedSpaceField = 2
+	usedSpaceAnnounceEpochField     = 1
+	usedSpaceAnnounceCIDField       = 2
+	usedSpaceAnnounceUsedSpaceField = 3
 
 	usedSpaceReqBodyAnnouncementsField = 1
 )
@@ -554,6 +555,13 @@ func (a *UsedSpaceAnnouncement) StableMarshal(buf []byte) ([]byte, error) {
 		err       error
 	)
 
+	n, err = protoutil.UInt64Marshal(usedSpaceAnnounceEpochField, buf[offset:], a.epoch)
+	if err != nil {
+		return nil, err
+	}
+
+	offset += n
+
 	n, err = protoutil.NestedStructureMarshal(usedSpaceAnnounceCIDField, buf[offset:], a.cid)
 	if err != nil {
 		return nil, err
@@ -574,6 +582,7 @@ func (a *UsedSpaceAnnouncement) StableSize() (size int) {
 		return 0
 	}
 
+	size += protoutil.UInt64Size(usedSpaceAnnounceEpochField, a.epoch)
 	size += protoutil.NestedStructureSize(usedSpaceAnnounceCIDField, a.cid)
 	size += protoutil.UInt64Size(usedSpaceAnnounceUsedSpaceField, a.usedSpace)
 
diff --git a/v2/container/marshal_test.go b/v2/container/marshal_test.go
index 5a86e88..dd6599f 100644
--- a/v2/container/marshal_test.go
+++ b/v2/container/marshal_test.go
@@ -455,6 +455,7 @@ func generateAnnounceRequestBody(n int) *container.AnnounceUsedSpaceRequestBody
 		cid.SetValue(buf)
 
 		a := new(container.UsedSpaceAnnouncement)
+		a.SetEpoch(rand.Uint64())
 		a.SetContainerID(cid)
 		a.SetUsedSpace(rand.Uint64())
 	}
diff --git a/v2/container/test/client_test.go b/v2/container/test/client_test.go
index da7cad0..177b9c9 100644
--- a/v2/container/test/client_test.go
+++ b/v2/container/test/client_test.go
@@ -418,10 +418,12 @@ func testAnnounceRequest() *container.AnnounceUsedSpaceRequest {
 	cid2.SetValue([]byte{4, 5, 6})
 
 	a1 := new(container.UsedSpaceAnnouncement)
+	a1.SetEpoch(20)
 	a1.SetUsedSpace(10)
 	a1.SetContainerID(cid1)
 
 	a2 := new(container.UsedSpaceAnnouncement)
+	a2.SetEpoch(20)
 	a2.SetUsedSpace(20)
 	a2.SetContainerID(cid2)
 
diff --git a/v2/container/types.go b/v2/container/types.go
index 07b65e6..004ddd7 100644
--- a/v2/container/types.go
+++ b/v2/container/types.go
@@ -94,6 +94,8 @@ type GetExtendedACLResponseBody struct {
 }
 
 type UsedSpaceAnnouncement struct {
+	epoch uint64
+
 	cid *refs.ContainerID
 
 	usedSpace uint64
@@ -917,6 +919,20 @@ func (r *GetExtendedACLResponse) SetVerificationHeader(v *session.ResponseVerifi
 	}
 }
 
+func (a *UsedSpaceAnnouncement) GetEpoch() uint64 {
+	if a != nil {
+		return a.epoch
+	}
+
+	return 0
+}
+
+func (a *UsedSpaceAnnouncement) SetEpoch(v uint64) {
+	if a != nil {
+		a.epoch = v
+	}
+}
+
 func (a *UsedSpaceAnnouncement) GetUsedSpace() uint64 {
 	if a != nil {
 		return a.usedSpace