diff --git a/common/docker/client.go b/common/docker/client.go
index 028bf05d..00100186 100644
--- a/common/docker/client.go
+++ b/common/docker/client.go
@@ -84,6 +84,15 @@ func (c *Client) Info() string {
 	return fmt.Sprintf("Docker API on %s: %v", c.Endpoint(), env)
 }
 
+func (c *Client) DockerVersion() string {
+	if env, err := c.Version(); err == nil {
+		if v, found := env.Map()["Version"]; found {
+			return v
+		}
+	}
+	return "unknown"
+}
+
 // AddObserver adds an observer for docker events
 func (c *Client) AddObserver(ob ContainerObserver) error {
 	go func() {
diff --git a/prog/weaver/checkpoint.go b/prog/weaver/checkpoint.go
new file mode 100644
index 00000000..fac1b089
--- /dev/null
+++ b/prog/weaver/checkpoint.go
@@ -0,0 +1,63 @@
+package main
+
+import (
+	"sync/atomic"
+	"syscall"
+	"time"
+
+	"github.com/weaveworks/go-checkpoint"
+)
+
+var checker *checkpoint.Checker
+var newVersion atomic.Value
+
+const (
+	updateCheckPeriod = 6 * time.Hour
+)
+
+func checkForUpdates(dockerVersion string, network string) {
+	newVersion.Store("")
+
+	handleResponse := func(r *checkpoint.CheckResponse, err error) {
+		if err != nil {
+			Log.Printf("Error checking version: %v", err)
+			return
+		}
+		if r.Outdated {
+			newVersion.Store(r.CurrentVersion)
+			Log.Printf("Weave version %s is available; please update at %s",
+				r.CurrentVersion, r.CurrentDownloadURL)
+		}
+	}
+
+	var uts syscall.Utsname
+	syscall.Uname(&uts)
+	flags := map[string]string{
+		"docker-version": dockerVersion,
+		"kernel-version": charsToString(uts.Release[:]),
+	}
+	if network != "" {
+		flags["network"] = network
+	}
+
+	// Start background version checking
+	params := checkpoint.CheckParams{
+		Product:       "weave-net",
+		Version:       version,
+		SignatureFile: "",
+		Flags:         flags,
+	}
+	checker = checkpoint.CheckInterval(&params, updateCheckPeriod, handleResponse)
+}
+
+func charsToString(ca []int8) string {
+	s := make([]byte, len(ca))
+	i := 0
+	for ; i < len(ca); i++ {
+		if ca[i] == 0 {
+			break
+		}
+		s[i] = uint8(ca[i])
+	}
+	return string(s[:i])
+}
diff --git a/prog/weaver/main.go b/prog/weaver/main.go
index 2a88dbbd..95cefc33 100644
--- a/prog/weaver/main.go
+++ b/prog/weaver/main.go
@@ -9,7 +9,6 @@ import (
 	"runtime"
 	"strconv"
 	"strings"
-	"sync/atomic"
 	"time"
 
 	"github.com/docker/docker/pkg/mflag"
@@ -17,7 +16,6 @@ import (
 	"github.com/pkg/profile"
 	"github.com/weaveworks/mesh"
 
-	"github.com/weaveworks/go-checkpoint"
 	"github.com/weaveworks/weave/common"
 	"github.com/weaveworks/weave/common/docker"
 	"github.com/weaveworks/weave/db"
@@ -30,8 +28,6 @@ import (
 )
 
 var version = "(unreleased version)"
-var checker *checkpoint.Checker
-var newVersion atomic.Value
 
 var Log = common.Log
 
@@ -53,34 +49,6 @@ type dnsConfig struct {
 	ResolvConf             string
 }
 
-const (
-	updateCheckPeriod = 6 * time.Hour
-)
-
-func checkForUpdates() {
-	newVersion.Store("")
-
-	handleResponse := func(r *checkpoint.CheckResponse, err error) {
-		if err != nil {
-			Log.Printf("Error checking version: %v", err)
-			return
-		}
-		if r.Outdated {
-			newVersion.Store(r.CurrentVersion)
-			Log.Printf("Weave version %s is available; please update at %s",
-				r.CurrentVersion, r.CurrentDownloadURL)
-		}
-	}
-
-	// Start background version checking
-	params := checkpoint.CheckParams{
-		Product:       "weave-net",
-		Version:       version,
-		SignatureFile: "",
-	}
-	checker = checkpoint.CheckInterval(&params, updateCheckPeriod, handleResponse)
-}
-
 func (c *ipamConfig) Enabled() bool {
 	var (
 		hasPeerCount = c.PeerCount > 0
@@ -238,8 +206,6 @@ func main() {
 
 	Log.Println("Command line options:", options())
 
-	checkForUpdates()
-
 	if prof != "" {
 		defer profile.Start(profile.CPUProfile, profile.ProfilePath(prof), profile.NoShutdownHook).Stop()
 	}
@@ -295,6 +261,13 @@ func main() {
 		}
 		dockerCli = dc
 	}
+
+	network := ""
+	if isAWSVPC {
+		network = "awsvpc"
+	}
+	checkForUpdates(dockerCli.DockerVersion(), network)
+
 	observeContainers := func(o docker.ContainerObserver) {
 		if dockerCli != nil {
 			if err := dockerCli.AddObserver(o); err != nil {
diff --git a/site/installing-weave.md b/site/installing-weave.md
index bab78d3b..7b7c81cb 100644
--- a/site/installing-weave.md
+++ b/site/installing-weave.md
@@ -31,12 +31,20 @@ With Weave Net downloaded onto your VMs or hosts, you are ready to launch a Weav
 Weave Net [periodically contacts Weaveworks servers for available
 versions](https://github.com/weaveworks/go-checkpoint).  New versions
 are announced in the log and in [the status
-summary](/site/troubleshooting.md#weave-status).  To disable this
-check, run the following before launching Weave Net:
+summary](/site/troubleshooting.md#weave-status).
+
+The information sent in this check is:
+
+ * Host UUID hash
+ * Kernel version
+ * Docker version
+ * Weave Net version
+ * Network mode, e.g. 'awsvpc'
+
+To disable this check, run the following before launching Weave Net:
 
     export CHECKPOINT_DISABLE=1
 
-
 ###Guides for Specific Platforms
 
 CoreOS users see [here](/guides/networking-docker-containers-with-weave-on-coreos/) for an example of installing Weave using cloud-config.
diff --git a/vendor/github.com/weaveworks/go-checkpoint b/vendor/github.com/weaveworks/go-checkpoint
index b6cc8365..62324982 160000
--- a/vendor/github.com/weaveworks/go-checkpoint
+++ b/vendor/github.com/weaveworks/go-checkpoint
@@ -1 +1 @@
-Subproject commit b6cc8365a31bccd0b19591ba4a68704082a17141
+Subproject commit 62324982ab514860761ec81e618664580513ffad