diff --git a/vendor/github.com/coreos/etcd/etcdserver/api/capability.go b/vendor/github.com/coreos/etcd/etcdserver/api/capability.go
new file mode 100644
index 0000000..eb34383
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/etcdserver/api/capability.go
@@ -0,0 +1,87 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package api
+
+import (
+	"sync"
+
+	"github.com/coreos/etcd/version"
+	"github.com/coreos/go-semver/semver"
+	"github.com/coreos/pkg/capnslog"
+)
+
+type Capability string
+
+const (
+	AuthCapability  Capability = "auth"
+	V3rpcCapability Capability = "v3rpc"
+)
+
+var (
+	plog = capnslog.NewPackageLogger("github.com/coreos/etcd", "etcdserver/api")
+
+	// capabilityMaps is a static map of version to capability map.
+	capabilityMaps = map[string]map[Capability]bool{
+		"3.0.0": {AuthCapability: true, V3rpcCapability: true},
+		"3.1.0": {AuthCapability: true, V3rpcCapability: true},
+		"3.2.0": {AuthCapability: true, V3rpcCapability: true},
+		"3.3.0": {AuthCapability: true, V3rpcCapability: true},
+	}
+
+	enableMapMu sync.RWMutex
+	// enabledMap points to a map in capabilityMaps
+	enabledMap map[Capability]bool
+
+	curVersion *semver.Version
+)
+
+func init() {
+	enabledMap = map[Capability]bool{
+		AuthCapability:  true,
+		V3rpcCapability: true,
+	}
+}
+
+// UpdateCapability updates the enabledMap when the cluster version increases.
+func UpdateCapability(v *semver.Version) {
+	if v == nil {
+		// if recovered but version was never set by cluster
+		return
+	}
+	enableMapMu.Lock()
+	if curVersion != nil && !curVersion.LessThan(*v) {
+		enableMapMu.Unlock()
+		return
+	}
+	curVersion = v
+	enabledMap = capabilityMaps[curVersion.String()]
+	enableMapMu.Unlock()
+	plog.Infof("enabled capabilities for version %s", version.Cluster(v.String()))
+}
+
+func IsCapabilityEnabled(c Capability) bool {
+	enableMapMu.RLock()
+	defer enableMapMu.RUnlock()
+	if enabledMap == nil {
+		return false
+	}
+	return enabledMap[c]
+}
+
+func EnableCapability(c Capability) {
+	enableMapMu.Lock()
+	defer enableMapMu.Unlock()
+	enabledMap[c] = true
+}