diff --git a/hamt/hamt_test.go b/hamt/hamt_test.go
index 8d0b93889..90377c2b1 100644
--- a/hamt/hamt_test.go
+++ b/hamt/hamt_test.go
@@ -162,7 +162,7 @@ func TestDirBuilding(t *testing.T) {
 
 	k := nd.Cid()
 
-	if k.String() != "QmY89TkSEVHykWMHDmyejSWFj9CYNtvzw4UwnT9xbc4Zjc" {
+	if k.String() != "QmWd277BEJs7VKLpd6Ki6mC12ESnKcFQAqF5JDJW4TpUjY" {
 		t.Fatalf("output didnt match what we expected (got %s)", k.String())
 	}
 }
diff --git a/io/dagreader_test.go b/io/dagreader_test.go
index de664370c..8a4d36f4a 100644
--- a/io/dagreader_test.go
+++ b/io/dagreader_test.go
@@ -204,7 +204,7 @@ func TestTypeFailures(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	node = mdag.NodeWithData(data)
+	node = unixfs.ProtoNodeCIDv1WithData(data)
 
 	if _, err := NewDagReader(ctx, node, dserv); err != ErrCantReadSymlinks {
 		t.Fatalf("excepted to get %v, got %v", ErrCantReadSymlinks, err)
@@ -216,7 +216,7 @@ func TestBadPBData(t *testing.T) {
 	ctx, closer := context.WithCancel(context.Background())
 	defer closer()
 
-	node := mdag.NodeWithData([]byte{42})
+	node := unixfs.ProtoNodeCIDv1WithData([]byte{42})
 	_, err := NewDagReader(ctx, node, dserv)
 	if err == nil {
 		t.Fatal("excepted error, got nil")
@@ -241,7 +241,7 @@ func TestMetadataNode(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	node := mdag.NodeWithData(data)
+	node := unixfs.ProtoNodeCIDv1WithData(data)
 
 	_, err = NewDagReader(ctx, node, dserv)
 	if err == nil {
diff --git a/io/directory_test.go b/io/directory_test.go
index ca67f5d25..6e3a5ea9d 100644
--- a/io/directory_test.go
+++ b/io/directory_test.go
@@ -222,12 +222,12 @@ func TestProductionLinkSize(t *testing.T) {
 	link, err := ipld.MakeLink(ft.EmptyDirNode())
 	assert.NoError(t, err)
 	link.Name = "directory_link_name"
-	assert.Equal(t, 53, productionLinkSize(link.Name, link.Cid))
+	assert.Equal(t, 55, productionLinkSize(link.Name, link.Cid))
 
 	link, err = ipld.MakeLink(ft.EmptyFileNode())
 	assert.NoError(t, err)
 	link.Name = "file_link_name"
-	assert.Equal(t, 48, productionLinkSize(link.Name, link.Cid))
+	assert.Equal(t, 50, productionLinkSize(link.Name, link.Cid))
 
 	ds := mdtest.Mock()
 	basicDir := newEmptyBasicDirectory(ds)
@@ -240,7 +240,7 @@ func TestProductionLinkSize(t *testing.T) {
 	link, err = ipld.MakeLink(basicDirNode)
 	assert.NoError(t, err)
 	link.Name = "basic_dir"
-	assert.Equal(t, 43, productionLinkSize(link.Name, link.Cid))
+	assert.Equal(t, 45, productionLinkSize(link.Name, link.Cid))
 }
 
 // Test HAMTDirectory <-> BasicDirectory switch based on directory size. The
diff --git a/mod/dagmodifier_test.go b/mod/dagmodifier_test.go
index 9870b2022..b07b1cc98 100644
--- a/mod/dagmodifier_test.go
+++ b/mod/dagmodifier_test.go
@@ -7,7 +7,6 @@ import (
 	"io/ioutil"
 	"testing"
 
-	dag "github.com/ipfs/go-merkledag"
 	h "github.com/ipfs/go-unixfs/importer/helpers"
 	trickle "github.com/ipfs/go-unixfs/importer/trickle"
 	uio "github.com/ipfs/go-unixfs/io"
@@ -416,7 +415,7 @@ func testDagTruncate(t *testing.T, opts testu.NodeOpts) {
 // if offset > curNode's size.
 func TestDagSync(t *testing.T) {
 	dserv := testu.GetDAGServ()
-	nd := dag.NodeWithData(unixfs.FilePBData(nil, 0))
+	nd := unixfs.ProtoNodeCIDv1WithData(unixfs.FilePBData(nil, 0))
 
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
diff --git a/unixfs.go b/unixfs.go
index 026b8bb3f..2e61754aa 100644
--- a/unixfs.go
+++ b/unixfs.go
@@ -356,14 +356,24 @@ func BytesForMetadata(m *Metadata) ([]byte, error) {
 	return proto.Marshal(pbd)
 }
 
+// ProtoNodeCIDv1WithData returns a ProtoNode with the given data and CIDv1.
+// FIXME: Switch to CIDv1 here until we decide if the switch should happen
+//  in `go-merkledag` itself (see https://github.com/ipfs/go-merkledag/issues/86).
+func ProtoNodeCIDv1WithData(data []byte) *dag.ProtoNode {
+	n := &dag.ProtoNode{}
+	n.SetData(data)
+	n.SetCidBuilder(dag.V1CidPrefix())
+	return n
+}
+
 // EmptyDirNode creates an empty folder Protonode.
 func EmptyDirNode() *dag.ProtoNode {
-	return dag.NodeWithData(FolderPBData())
+	return ProtoNodeCIDv1WithData(FolderPBData())
 }
 
 // EmptyFileNode creates an empty file Protonode.
 func EmptyFileNode() *dag.ProtoNode {
-	return dag.NodeWithData(FilePBData(nil, 0))
+	return ProtoNodeCIDv1WithData(FilePBData(nil, 0))
 }
 
 // ReadUnixFSNodeData extracts the UnixFS data from an IPLD node.
diff --git a/version.json b/version.json
index 9ed87d762..372b6eab3 100644
--- a/version.json
+++ b/version.json
@@ -1,3 +1,3 @@
 {
-  "version": "v0.3.1"
+  "version": "v0.4.0"
 }