diff --git a/cmd/abci-cli/abci-cli.go b/cmd/abci-cli/abci-cli.go
index 7655a7750..bd754436d 100644
--- a/cmd/abci-cli/abci-cli.go
+++ b/cmd/abci-cli/abci-cli.go
@@ -79,7 +79,7 @@ var RootCmd = &cobra.Command{
 				return err
 			}
 			client.SetLogger(logger.With("module", "abci-client"))
-			if err := client.Start(); err != nil {
+			if _, err := client.Start(); err != nil {
 				return err
 			}
 		}
@@ -631,7 +631,7 @@ func cmdCounter(cmd *cobra.Command, args []string) error {
 		return err
 	}
 	srv.SetLogger(logger.With("module", "abci-server"))
-	if err := srv.Start(); err != nil {
+	if _, err := srv.Start(); err != nil {
 		return err
 	}
 
@@ -661,7 +661,7 @@ func cmdDummy(cmd *cobra.Command, args []string) error {
 		return err
 	}
 	srv.SetLogger(logger.With("module", "abci-server"))
-	if err := srv.Start(); err != nil {
+	if _, err := srv.Start(); err != nil {
 		return err
 	}
 
diff --git a/example/dummy/dummy.go b/example/dummy/dummy.go
index c8fb0f376..29ba1ac64 100644
--- a/example/dummy/dummy.go
+++ b/example/dummy/dummy.go
@@ -6,7 +6,6 @@ import (
 
 	"github.com/tendermint/abci/example/code"
 	"github.com/tendermint/abci/types"
-	wire "github.com/tendermint/go-wire"
 	"github.com/tendermint/iavl"
 	dbm "github.com/tendermint/tmlibs/db"
 )
@@ -20,7 +19,7 @@ type DummyApplication struct {
 }
 
 func NewDummyApplication() *DummyApplication {
-	state := iavl.NewVersionedTree(0, dbm.NewMemDB())
+	state := iavl.NewVersionedTree(dbm.NewMemDB(), 0)
 	return &DummyApplication{state: state}
 }
 
@@ -56,9 +55,7 @@ func (app *DummyApplication) Commit() types.ResponseCommit {
 	var err error
 
 	if app.state.Size() > 0 {
-		// just add one more to height (kind of arbitrarily stupid)
-		height := app.state.LatestVersion() + 1
-		hash, err = app.state.SaveVersion(height)
+		hash, _, err = app.state.SaveVersion()
 		if err != nil {
 			// if this wasn't a dummy app, we'd do something smarter
 			panic(err)
@@ -78,7 +75,7 @@ func (app *DummyApplication) Query(reqQuery types.RequestQuery) (resQuery types.
 		resQuery.Index = -1 // TODO make Proof return index
 		resQuery.Key = reqQuery.Data
 		resQuery.Value = value
-		resQuery.Proof = wire.BinaryBytes(proof)
+		resQuery.Proof = proof.Bytes()
 		if value != nil {
 			resQuery.Log = "exists"
 		} else {
diff --git a/example/dummy/dummy_test.go b/example/dummy/dummy_test.go
index 530c01c22..dd3b27791 100644
--- a/example/dummy/dummy_test.go
+++ b/example/dummy/dummy_test.go
@@ -41,9 +41,9 @@ func testDummy(t *testing.T, app types.Application, tx []byte, key, value string
 	})
 	require.EqualValues(t, code.CodeTypeOK, resQuery.Code)
 	require.Equal(t, value, string(resQuery.Value))
-	proof, err := iavl.ReadKeyExistsProof(resQuery.Proof)
+	proof, err := iavl.ReadKeyProof(resQuery.Proof)
 	require.Nil(t, err)
-	err = proof.Verify([]byte(key), resQuery.Value, proof.RootHash)
+	err = proof.Verify([]byte(key), resQuery.Value, proof.Root())
 	require.Nil(t, err, "%+v", err) // NOTE: we have no way to verify the RootHash
 }
 
@@ -215,14 +215,14 @@ func makeSocketClientServer(app types.Application, name string) (abcicli.Client,
 
 	server := abciserver.NewSocketServer(socket, app)
 	server.SetLogger(logger.With("module", "abci-server"))
-	if err := server.Start(); err != nil {
+	if _, err := server.Start(); err != nil {
 		return nil, nil, err
 	}
 
 	// Connect to the socket
 	client := abcicli.NewSocketClient(socket, false)
 	client.SetLogger(logger.With("module", "abci-client"))
-	if err := client.Start(); err != nil {
+	if _, err := client.Start(); err != nil {
 		server.Stop()
 		return nil, nil, err
 	}
@@ -238,13 +238,13 @@ func makeGRPCClientServer(app types.Application, name string) (abcicli.Client, c
 	gapp := types.NewGRPCApplication(app)
 	server := abciserver.NewGRPCServer(socket, gapp)
 	server.SetLogger(logger.With("module", "abci-server"))
-	if err := server.Start(); err != nil {
+	if _, err := server.Start(); err != nil {
 		return nil, nil, err
 	}
 
 	client := abcicli.NewGRPCClient(socket, true)
 	client.SetLogger(logger.With("module", "abci-client"))
-	if err := client.Start(); err != nil {
+	if _, err := client.Start(); err != nil {
 		server.Stop()
 		return nil, nil, err
 	}
@@ -310,8 +310,8 @@ func testClient(t *testing.T, app abcicli.Client, tx []byte, key, value string)
 	require.Nil(t, err)
 	require.Equal(t, code.CodeTypeOK, resQuery.Code)
 	require.Equal(t, value, string(resQuery.Value))
-	proof, err := iavl.ReadKeyExistsProof(resQuery.Proof)
+	proof, err := iavl.ReadKeyProof(resQuery.Proof)
 	require.Nil(t, err)
-	err = proof.Verify([]byte(key), resQuery.Value, proof.RootHash)
+	err = proof.Verify([]byte(key), resQuery.Value, proof.Root())
 	require.Nil(t, err, "%+v", err) // NOTE: we have no way to verify the RootHash
 }
diff --git a/example/dummy/persistent_dummy.go b/example/dummy/persistent_dummy.go
index 4d272246c..a41279b6e 100644
--- a/example/dummy/persistent_dummy.go
+++ b/example/dummy/persistent_dummy.go
@@ -40,7 +40,7 @@ func NewPersistentDummyApplication(dbDir string) *PersistentDummyApplication {
 		panic(err)
 	}
 
-	stateTree := iavl.NewVersionedTree(500, db)
+	stateTree := iavl.NewVersionedTree(db, 500)
 	stateTree.Load()
 
 	return &PersistentDummyApplication{
@@ -55,8 +55,7 @@ func (app *PersistentDummyApplication) SetLogger(l log.Logger) {
 
 func (app *PersistentDummyApplication) Info(req types.RequestInfo) types.ResponseInfo {
 	res := app.app.Info(req)
-	var latestVersion uint64 = app.app.state.LatestVersion() // TODO: change to int64
-	res.LastBlockHeight = int64(latestVersion)
+	res.LastBlockHeight = app.app.state.Version64()
 	res.LastBlockAppHash = app.app.state.Hash()
 	return res
 }
@@ -87,11 +86,11 @@ func (app *PersistentDummyApplication) CheckTx(tx []byte) types.ResponseCheckTx
 func (app *PersistentDummyApplication) Commit() types.ResponseCommit {
 
 	// Save a new version for next height
-	height := app.app.state.LatestVersion() + 1
+	var height int64
 	var appHash []byte
 	var err error
 
-	appHash, err = app.app.state.SaveVersion(height)
+	appHash, height, err = app.app.state.SaveVersion()
 	if err != nil {
 		// if this wasn't a dummy app, we'd do something smarter
 		panic(err)
diff --git a/example/example_test.go b/example/example_test.go
index dfa38a398..2a93f2463 100644
--- a/example/example_test.go
+++ b/example/example_test.go
@@ -42,7 +42,7 @@ func testStream(t *testing.T, app types.Application) {
 	// Start the listener
 	server := abciserver.NewSocketServer("unix://test.sock", app)
 	server.SetLogger(log.TestingLogger().With("module", "abci-server"))
-	if err := server.Start(); err != nil {
+	if _, err := server.Start(); err != nil {
 		t.Fatalf("Error starting socket server: %v", err.Error())
 	}
 	defer server.Stop()
@@ -50,7 +50,7 @@ func testStream(t *testing.T, app types.Application) {
 	// Connect to the socket
 	client := abcicli.NewSocketClient("unix://test.sock", false)
 	client.SetLogger(log.TestingLogger().With("module", "abci-client"))
-	if err := client.Start(); err != nil {
+	if _, err := client.Start(); err != nil {
 		t.Fatalf("Error starting socket client: %v", err.Error())
 	}
 	defer client.Stop()
@@ -115,7 +115,7 @@ func testGRPCSync(t *testing.T, app *types.GRPCApplication) {
 	// Start the listener
 	server := abciserver.NewGRPCServer("unix://test.sock", app)
 	server.SetLogger(log.TestingLogger().With("module", "abci-server"))
-	if err := server.Start(); err != nil {
+	if _, err := server.Start(); err != nil {
 		t.Fatalf("Error starting GRPC server: %v", err.Error())
 	}
 	defer server.Stop()
diff --git a/glide.lock b/glide.lock
index f96fd1c08..6d22b46d1 100644
--- a/glide.lock
+++ b/glide.lock
@@ -1,32 +1,29 @@
-hash: 6cb2c869c8ce7d9e43b1e8930b9b1bc974ebb3d36d4b704fc78b77efba956a13
-updated: 2017-11-30T17:08:29.176515576-05:00
+hash: 2fe5021646e1cdb80999a9fe0a88a6b695409fa9891b28a97682d2782c9d26ab
+updated: 2017-12-26T00:33:47.921468008-08:00
 imports:
 - name: github.com/btcsuite/btcd
-  version: 2e60448ffcc6bf78332d1fe590260095f554dd78
+  version: c7588cbf7690cd9f047a28efa2dcd8f2435a4e5e
   subpackages:
   - btcec
 - name: github.com/go-kit/kit
-  version: e3b2152e0063c5f05efea89ecbe297852af2a92d
+  version: e2b298466b32c7cd5579a9b9b07e968fc9d9452c
   subpackages:
   - log
   - log/level
   - log/term
 - name: github.com/go-logfmt/logfmt
   version: 390ab7935ee28ec6b286364bba9b4dd6410cb3d5
-- name: github.com/go-playground/locales
-  version: e4cbcb5d0652150d40ad0646651076b6bd2be4f6
-  subpackages:
-  - currency
-- name: github.com/go-playground/universal-translator
-  version: 71201497bace774495daed26a3874fd339e0b538
 - name: github.com/go-stack/stack
-  version: 259ab82a6cad3992b4e21ff5cac294ccb06474bc
+  version: 817915b46b97fd7bb80e8ab6b69f01a53ac3eebf
 - name: github.com/gogo/protobuf
   version: 342cbe0a04158f6dcb03ca0079991a51a4248c02
   subpackages:
   - gogoproto
+  - jsonpb
   - proto
   - protoc-gen-gogo/descriptor
+  - sortkeys
+  - types
 - name: github.com/golang/protobuf
   version: 1e59b77b52bf8e4b449a57e6f79f21226d571845
   subpackages:
@@ -44,13 +41,13 @@ imports:
 - name: github.com/kr/logfmt
   version: b84e30acd515aadc4b783ad4ff83aff3299bdfe0
 - name: github.com/pkg/errors
-  version: f15c970de5b76fac0b59abb32d62c17cc7bed265
+  version: 645ef00459ed84a119197bfb8d8205042c6df63d
 - name: github.com/spf13/cobra
   version: 7b2c5ac9fc04fc5efafb60700713d4fa609b777b
 - name: github.com/spf13/pflag
   version: 4c012f6dcd9546820e378d0bdda4d8fc772cdfea
 - name: github.com/syndtr/goleveldb
-  version: adf24ef3f94bd13ec4163060b21a5678f22b429b
+  version: b89cc31ef7977104127d34c1bd31ebd1a9db2199
   subpackages:
   - leveldb
   - leveldb/cache
@@ -70,22 +67,22 @@ imports:
   - edwards25519
   - extra25519
 - name: github.com/tendermint/go-crypto
-  version: b4f04f196cd719660e43b91202cd60d9a95b1837
+  version: 9472476a8b5814d42b96881e28a01536acfdabb3
 - name: github.com/tendermint/go-wire
-  version: 5ab49b4c6ad674da6b81442911cf713ef0afb544
+  version: 27be46e25124ddf775e23317a83647ce62a93f6b
   subpackages:
   - data
 - name: github.com/tendermint/iavl
-  version: 595f3dcd5b6cd4a292e90757ae6d367fd7a6e653
+  version: 7f42f4ea5187ac0184ded22a038e77faba035606
 - name: github.com/tendermint/tmlibs
-  version: 21fb7819891997c96838308b4eba5a50b07ff03f
+  version: 6ec8c1602f22f41fc320da05c3a80acebf2c23bd
   subpackages:
   - common
   - db
   - log
   - process
 - name: golang.org/x/crypto
-  version: 94eea52f7b742c7cbe0b03b22f0c4c8631ece122
+  version: edd5e9b0879d13ee6970a50153d85b8fec9f7686
   subpackages:
   - nacl/secretbox
   - openpgp/armor
@@ -94,7 +91,7 @@ imports:
   - ripemd160
   - salsa20/salsa
 - name: golang.org/x/net
-  version: a8b9294777976932365dabb6640cf1468d95c70f
+  version: d866cfc389cec985d6fda2859936a575a55a3ab6
   subpackages:
   - context
   - http2
@@ -111,7 +108,7 @@ imports:
   - unicode/bidi
   - unicode/norm
 - name: google.golang.org/genproto
-  version: 7f0da29060c682909f650ad8ed4e515bd74fa12a
+  version: a8101f21cf983e773d0c1133ebc5424792003214
   subpackages:
   - googleapis/rpc/status
 - name: google.golang.org/grpc
@@ -133,11 +130,9 @@ imports:
   - status
   - tap
   - transport
-- name: gopkg.in/go-playground/validator.v9
-  version: 61caf9d3038e1af346dbf5c2e16f6678e1548364
 testImports:
 - name: github.com/davecgh/go-spew
-  version: 04cdfd42973bb9c8589fd6a731800cf222fde1a9
+  version: 6d212800a42e8ab5c146b8ace3490ee17e5225f9
   subpackages:
   - spew
 - name: github.com/pmezard/go-difflib
@@ -145,7 +140,7 @@ testImports:
   subpackages:
   - difflib
 - name: github.com/stretchr/testify
-  version: 2aa2c176b9dab406a6970f6a55f513e8a8c8b18f
+  version: 69483b4bd14f5845b5a1e55bca19e954e827f1d0
   subpackages:
   - assert
   - require
diff --git a/glide.yaml b/glide.yaml
index 88f49dde4..1fd8c7921 100644
--- a/glide.yaml
+++ b/glide.yaml
@@ -7,15 +7,15 @@ import:
 - package: github.com/spf13/cobra
   version: v0.0.1
 - package: github.com/tendermint/go-crypto
-  version: develop
+  version: sdk2
 - package: github.com/tendermint/go-wire
   version: develop
   subpackages:
   - data
 - package: github.com/tendermint/iavl
-  version: develop
+  version: sdk2
 - package: github.com/tendermint/tmlibs
-  version: develop
+  version: sdk2
   subpackages:
   - common
   - db
diff --git a/tests/client_server_test.go b/tests/client_server_test.go
index 3d74478bc..d354fc058 100644
--- a/tests/client_server_test.go
+++ b/tests/client_server_test.go
@@ -17,11 +17,11 @@ func TestClientServerNoAddrPrefix(t *testing.T) {
 
 	server, err := abciserver.NewServer(addr, transport, app)
 	assert.NoError(t, err, "expected no error on NewServer")
-	err = server.Start()
+	_, err = server.Start()
 	assert.NoError(t, err, "expected no error on server.Start")
 
 	client, err := abciclient.NewClient(addr, transport, true)
 	assert.NoError(t, err, "expected no error on NewClient")
-	err = client.Start()
+	_, err = client.Start()
 	assert.NoError(t, err, "expected no error on client.Start")
 }
diff --git a/tests/test_app/app.go b/tests/test_app/app.go
index f04036216..d55fb1601 100644
--- a/tests/test_app/app.go
+++ b/tests/test_app/app.go
@@ -18,7 +18,7 @@ func startClient(abciType string) abcicli.Client {
 	}
 	logger := log.NewTMLogger(log.NewSyncWriter(os.Stdout))
 	client.SetLogger(logger.With("module", "abcicli"))
-	if err := client.Start(); err != nil {
+	if _, err := client.Start(); err != nil {
 		panicf("connecting to abci_app: %v", err.Error())
 	}