deleted file mode 100644

@@ -1,47 +0,0 @@

-package middleware

-

-import (

-	"net/http"

-	"strings"

-

-	"github.com/Sirupsen/logrus"

-	"github.com/docker/docker/api/server/httputils"

-	"github.com/docker/docker/api/types/versions"

-	"golang.org/x/net/context"

-)

-

-// UserAgentMiddleware is a middleware that

-// validates the client user-agent.

-type UserAgentMiddleware struct {

-	serverVersion string

-}

-

-// NewUserAgentMiddleware creates a new UserAgentMiddleware

-// with the server version.

-func NewUserAgentMiddleware(s string) UserAgentMiddleware {

-	return UserAgentMiddleware{

-		serverVersion: s,

-	}

-}

-

-// WrapHandler returns a new handler function wrapping the previous one in the request chain.

-func (u UserAgentMiddleware) WrapHandler(handler func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error) func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {

-	return func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {

-		ctx = context.WithValue(ctx, httputils.UAStringKey, r.Header.Get("User-Agent"))

-

-		if strings.Contains(r.Header.Get("User-Agent"), "Docker-Client/") {

-			userAgent := strings.Split(r.Header.Get("User-Agent"), "/")

-

-			// v1.20 onwards includes the GOOS of the client after the version

-			// such as Docker/1.7.0 (linux)

-			if len(userAgent) == 2 && strings.Contains(userAgent[1], " ") {

-				userAgent[1] = strings.Split(userAgent[1], " ")[0]

-			}

-

-			if len(userAgent) == 2 && !versions.Equal(u.serverVersion, userAgent[1]) {

-				logrus.Debugf("Client and server don't have the same version (client: %s, server: %s)", userAgent[1], u.serverVersion)

-			}

-		}

-		return handler(ctx, w, r, vars)

-	}

-}

@@ -36,15 +36,13 @@ func (v VersionMiddleware) WrapHandler(handler func(ctx context.Context, w http.

 			apiVersion = v.defaultVersion

 		}

-		if versions.GreaterThan(apiVersion, v.defaultVersion) {

-			return errors.NewBadRequestError(fmt.Errorf("client is newer than server (client API version: %s, server API version: %s)", apiVersion, v.defaultVersion))

-		}

 		if versions.LessThan(apiVersion, v.minVersion) {

 			return errors.NewBadRequestError(fmt.Errorf("client version %s is too old. Minimum supported API version is %s, please upgrade your client to a newer version", apiVersion, v.minVersion))

 		}

 		header := fmt.Sprintf("Docker/%s (%s)", v.serverVersion, runtime.GOOS)

 		w.Header().Set("Server", header)

+		w.Header().Set("API-Version", v.defaultVersion)

 		ctx = context.WithValue(ctx, "api-version", apiVersion)

 		return handler(ctx, w, r, vars)

 	}

@@ -54,10 +54,4 @@ func TestVersionMiddlewareWithErrors(t *testing.T) {

 	if !strings.Contains(err.Error(), "client version 0.1 is too old. Minimum supported API version is 1.2.0") {

 		t.Fatalf("Expected too old client error, got %v", err)

 	}

-

-	vars["version"] = "100000"

-	err = h(ctx, resp, req, vars)

-	if !strings.Contains(err.Error(), "client is newer than server") {

-		t.Fatalf("Expected client newer than server error, got %v", err)

-	}

 }

@@ -128,7 +128,7 @@ func (s *Server) makeHTTPHandler(handler httputils.APIFunc) http.HandlerFunc {

 		// apply to all requests. Data that is specific to the

 		// immediate function being called should still be passed

 		// as 'args' on the function call.

-		ctx := context.Background()

+		ctx := context.WithValue(context.Background(), httputils.UAStringKey, r.Header.Get("User-Agent"))

 		handlerFunc := s.handlerWithGlobalMiddlewares(handler)

 		vars := mux.Vars(r)

@@ -128,6 +128,13 @@ type ContainerProcessList struct {

 	Titles    []string

 }

+// Info contains response of Remote API:

+// GET "/_ping"

+type Ping struct {

+	APIVersion   string

+	Experimental bool

+}

+

 // Version contains response of Remote API:

 // GET "/version"

 type Version struct {

@@ -1,8 +1,6 @@

 package checkpoint

 import (

-	"fmt"

-

 	"github.com/docker/docker/cli"

 	"github.com/docker/docker/cli/command"

 	"github.com/spf13/cobra"

@@ -15,9 +13,10 @@ func NewCheckpointCommand(dockerCli *command.DockerCli) *cobra.Command {

 		Short: "Manage checkpoints",

 		Args:  cli.NoArgs,

 		Run: func(cmd *cobra.Command, args []string) {

-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())

+			cmd.SetOutput(dockerCli.Err())

+			cmd.HelpFunc()(cmd, args)

 		},

-		Tags: map[string]string{"experimental": ""},

+		Tags: map[string]string{"experimental": "", "version": "1.25"},

 	}

 	cmd.AddCommand(

 		newCreateCommand(dockerCli),

@@ -10,6 +10,7 @@ import (

 	"runtime"

 	"github.com/docker/docker/api"

+	"github.com/docker/docker/api/types/versions"

 	cliflags "github.com/docker/docker/cli/flags"

 	"github.com/docker/docker/cliconfig"

 	"github.com/docker/docker/cliconfig/configfile"

@@ -32,21 +33,24 @@ type Streams interface {

 // DockerCli represents the docker command line client.

 // Instances of the client can be returned from NewDockerCli.

 type DockerCli struct {

-	configFile *configfile.ConfigFile

-	in         *InStream

-	out        *OutStream

-	err        io.Writer

-	keyFile    string

-	client     client.APIClient

+	configFile      *configfile.ConfigFile

+	in              *InStream

+	out             *OutStream

+	err             io.Writer

+	keyFile         string

+	client          client.APIClient

+	hasExperimental bool

+	defaultVersion  string

 }

-// HasExperimental returns true if experimental features are accessible

+// HasExperimental returns true if experimental features are accessible.

 func (cli *DockerCli) HasExperimental() bool {

-	if cli.client == nil {

-		return false

-	}

-	enabled, _ := cli.client.Ping(context.Background())

-	return enabled

+	return cli.hasExperimental

+}

+

+// DefaultVersion returns api.defaultVersion of DOCKER_API_VERSION if specified.

+func (cli *DockerCli) DefaultVersion() string {

+	return cli.defaultVersion

 }

 // Client returns the APIClient

@@ -93,12 +97,28 @@ func (cli *DockerCli) Initialize(opts *cliflags.ClientOptions) error {

 	if err != nil {

 		return err

 	}

+

+	cli.defaultVersion = cli.client.ClientVersion()

+

 	if opts.Common.TrustKey == "" {

 		cli.keyFile = filepath.Join(cliconfig.ConfigDir(), cliflags.DefaultTrustKeyFile)

 	} else {

 		cli.keyFile = opts.Common.TrustKey

 	}

+	if ping, err := cli.client.Ping(context.Background()); err == nil {

+		cli.hasExperimental = ping.Experimental

+

+		// since the new header was added in 1.25, assume server is 1.24 if header is not present.

+		if ping.APIVersion == "" {

+			ping.APIVersion = "1.24"

+		}

+

+		// if server version is lower than the current cli, downgrade

+		if versions.LessThan(ping.APIVersion, cli.client.ClientVersion()) {

+			cli.client.UpdateClientVersion(ping.APIVersion)

+		}

+	}

 	return nil

 }

@@ -1,8 +1,6 @@

 package container

 import (

-	"fmt"

-

 	"github.com/spf13/cobra"

 	"github.com/docker/docker/cli"

@@ -16,7 +14,8 @@ func NewContainerCommand(dockerCli *command.DockerCli) *cobra.Command {

 		Short: "Manage containers",

 		Args:  cli.NoArgs,

 		Run: func(cmd *cobra.Command, args []string) {

-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())

+			cmd.SetOutput(dockerCli.Err())

+			cmd.HelpFunc()(cmd, args)

 		},

 	}

 	cmd.AddCommand(

@@ -59,6 +59,7 @@ func NewExecCommand(dockerCli *command.DockerCli) *cobra.Command {

 	flags.StringVarP(&opts.user, "user", "u", "", "Username or UID (format: <name|uid>[:<group|gid>])")

 	flags.BoolVarP(&opts.privileged, "privileged", "", false, "Give extended privileges to the command")

 	flags.VarP(opts.env, "env", "e", "Set environment variables")

+	flags.SetAnnotation("env", "version", []string{"1.25"})

 	return cmd

 }

@@ -35,6 +35,7 @@ func NewPruneCommand(dockerCli *command.DockerCli) *cobra.Command {

 			fmt.Fprintln(dockerCli.Out(), "Total reclaimed space:", units.HumanSize(float64(spaceReclaimed)))

 			return nil

 		},

+		Tags: map[string]string{"version": "1.25"},

 	}

 	flags := cmd.Flags()

@@ -113,6 +113,7 @@ func NewBuildCommand(dockerCli *command.DockerCli) *cobra.Command {

 	flags.BoolVar(&options.squash, "squash", false, "Squash newly built layers into a single new layer")

 	flags.SetAnnotation("squash", "experimental", nil)

+	flags.SetAnnotation("squash", "version", []string{"1.25"})

 	return cmd

 }

@@ -144,7 +145,7 @@ func runBuild(dockerCli *command.DockerCli, options buildOptions) error {

 		progBuff      io.Writer

 		buildBuff     io.Writer

 	)

-	

+

 	specifiedContext := options.context

 	progBuff = dockerCli.Out()

 	buildBuff = dockerCli.Out()

@@ -1,8 +1,6 @@

 package image

 import (

-	"fmt"

-

 	"github.com/spf13/cobra"

 	"github.com/docker/docker/cli"

@@ -16,7 +14,8 @@ func NewImageCommand(dockerCli *command.DockerCli) *cobra.Command {

 		Short: "Manage images",

 		Args:  cli.NoArgs,

 		Run: func(cmd *cobra.Command, args []string) {

-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())

+			cmd.SetOutput(dockerCli.Err())

+			cmd.HelpFunc()(cmd, args)

 		},

 	}

 	cmd.AddCommand(

@@ -33,6 +32,5 @@ func NewImageCommand(dockerCli *command.DockerCli) *cobra.Command {

 		newInspectCommand(dockerCli),

 		NewPruneCommand(dockerCli),

 	)

-

 	return cmd

 }

@@ -36,6 +36,7 @@ func NewPruneCommand(dockerCli *command.DockerCli) *cobra.Command {

 			fmt.Fprintln(dockerCli.Out(), "Total reclaimed space:", units.HumanSize(float64(spaceReclaimed)))

 			return nil

 		},

+		Tags: map[string]string{"version": "1.25"},

 	}

 	flags := cmd.Flags()

@@ -1,8 +1,6 @@

 package network

 import (

-	"fmt"

-

 	"github.com/spf13/cobra"

 	"github.com/docker/docker/cli"

@@ -16,7 +14,8 @@ func NewNetworkCommand(dockerCli *command.DockerCli) *cobra.Command {

 		Short: "Manage networks",

 		Args:  cli.NoArgs,

 		Run: func(cmd *cobra.Command, args []string) {

-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())

+			cmd.SetOutput(dockerCli.Err())

+			cmd.HelpFunc()(cmd, args)

 		},

 	}

 	cmd.AddCommand(

@@ -33,6 +33,7 @@ func NewPruneCommand(dockerCli *command.DockerCli) *cobra.Command {

 			}

 			return nil

 		},

+		Tags: map[string]string{"version": "1.25"},

 	}

 	flags := cmd.Flags()

@@ -1,8 +1,6 @@

 package node

 import (

-	"fmt"

-

 	"github.com/docker/docker/cli"

 	"github.com/docker/docker/cli/command"

 	apiclient "github.com/docker/docker/client"

@@ -17,7 +15,8 @@ func NewNodeCommand(dockerCli *command.DockerCli) *cobra.Command {

 		Short: "Manage Swarm nodes",

 		Args:  cli.NoArgs,

 		Run: func(cmd *cobra.Command, args []string) {

-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())

+			cmd.SetOutput(dockerCli.Err())

+			cmd.HelpFunc()(cmd, args)

 		},

 	}

 	cmd.AddCommand(

@@ -1,8 +1,6 @@

 package plugin

 import (

-	"fmt"

-

 	"github.com/docker/docker/cli"

 	"github.com/docker/docker/cli/command"

 	"github.com/spf13/cobra"

@@ -15,7 +13,8 @@ func NewPluginCommand(dockerCli *command.DockerCli) *cobra.Command {

 		Short: "Manage plugins",

 		Args:  cli.NoArgs,

 		Run: func(cmd *cobra.Command, args []string) {

-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())

+			cmd.SetOutput(dockerCli.Err())

+			cmd.HelpFunc()(cmd, args)

 		},

 		Tags: map[string]string{"experimental": ""},

 	}

@@ -1,8 +1,6 @@

 package service

 import (

-	"fmt"

-

 	"github.com/spf13/cobra"

 	"github.com/docker/docker/cli"

@@ -16,7 +14,8 @@ func NewServiceCommand(dockerCli *command.DockerCli) *cobra.Command {

 		Short: "Manage services",

 		Args:  cli.NoArgs,

 		Run: func(cmd *cobra.Command, args []string) {

-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())

+			cmd.SetOutput(dockerCli.Err())

+			cmd.HelpFunc()(cmd, args)

 		},

 	}

 	cmd.AddCommand(

@@ -1,8 +1,6 @@

 package stack

 import (

-	"fmt"

-

 	"github.com/docker/docker/cli"

 	"github.com/docker/docker/cli/command"

 	"github.com/spf13/cobra"

@@ -15,9 +13,10 @@ func NewStackCommand(dockerCli *command.DockerCli) *cobra.Command {

 		Short: "Manage Docker stacks",

 		Args:  cli.NoArgs,

 		Run: func(cmd *cobra.Command, args []string) {

-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())

+			cmd.SetOutput(dockerCli.Err())

+			cmd.HelpFunc()(cmd, args)

 		},

-		Tags: map[string]string{"experimental": ""},

+		Tags: map[string]string{"experimental": "", "version": "1.25"},

 	}

 	cmd.AddCommand(

 		newConfigCommand(dockerCli),

@@ -36,7 +36,7 @@ func newDeployCommand(dockerCli *command.DockerCli) *cobra.Command {

 			opts.namespace = strings.TrimSuffix(args[0], ".dab")

 			return runDeploy(dockerCli, opts)

 		},

-		Tags: map[string]string{"experimental": ""},

+		Tags: map[string]string{"experimental": "", "version": "1.25"},

 	}

 	flags := cmd.Flags()

@@ -1,8 +1,6 @@

 package swarm

 import (

-	"fmt"

-

 	"github.com/spf13/cobra"

 	"github.com/docker/docker/cli"

@@ -16,7 +14,8 @@ func NewSwarmCommand(dockerCli *command.DockerCli) *cobra.Command {

 		Short: "Manage Swarm",

 		Args:  cli.NoArgs,

 		Run: func(cmd *cobra.Command, args []string) {

-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())

+			cmd.SetOutput(dockerCli.Err())

+			cmd.HelpFunc()(cmd, args)

 		},

 	}

 	cmd.AddCommand(

@@ -1,8 +1,6 @@

 package system

 import (

-	"fmt"

-

 	"github.com/spf13/cobra"

 	"github.com/docker/docker/cli"

@@ -16,7 +14,8 @@ func NewSystemCommand(dockerCli *command.DockerCli) *cobra.Command {

 		Short: "Manage Docker",

 		Args:  cli.NoArgs,

 		Run: func(cmd *cobra.Command, args []string) {

-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())

+			cmd.SetOutput(dockerCli.Err())

+			cmd.HelpFunc()(cmd, args)

 		},

 	}

 	cmd.AddCommand(

@@ -25,5 +24,6 @@ func NewSystemCommand(dockerCli *command.DockerCli) *cobra.Command {

 		NewDiskUsageCommand(dockerCli),

 		NewPruneCommand(dockerCli),

 	)

+

 	return cmd

 }

@@ -23,6 +23,7 @@ func NewDiskUsageCommand(dockerCli *command.DockerCli) *cobra.Command {

 		RunE: func(cmd *cobra.Command, args []string) error {

 			return runDiskUsage(dockerCli, opts)

 		},

+		Tags: map[string]string{"version": "1.25"},

 	}

 	flags := cmd.Flags()

@@ -26,6 +26,7 @@ func NewPruneCommand(dockerCli *command.DockerCli) *cobra.Command {

 		RunE: func(cmd *cobra.Command, args []string) error {

 			return runPrune(dockerCli, opts)

 		},

+		Tags: map[string]string{"version": "1.25"},

 	}

 	flags := cmd.Flags()

@@ -1,6 +1,7 @@

 package system

 import (

+	"fmt"

 	"runtime"

 	"time"

@@ -70,10 +71,15 @@ func runVersion(dockerCli *command.DockerCli, opts *versionOptions) error {

 			Status: "Template parsing error: " + err.Error()}

 	}

+	APIVersion := dockerCli.Client().ClientVersion()

+	if defaultAPIVersion := dockerCli.DefaultVersion(); APIVersion != defaultAPIVersion {

+		APIVersion = fmt.Sprintf("%s (downgraded from %s)", APIVersion, defaultAPIVersion)

+	}

+

 	vd := types.VersionResponse{

 		Client: &types.Version{

 			Version:    dockerversion.Version,

-			APIVersion: dockerCli.Client().ClientVersion(),

+			APIVersion: APIVersion,

 			GoVersion:  runtime.Version(),

 			GitCommit:  dockerversion.GitCommit,

 			BuildTime:  dockerversion.BuildTime,

@@ -1,8 +1,6 @@

 package volume

 import (

-	"fmt"

-

 	"github.com/spf13/cobra"

 	"github.com/docker/docker/cli"

@@ -17,7 +15,8 @@ func NewVolumeCommand(dockerCli *command.DockerCli) *cobra.Command {

 		Long:  volumeDescription,

 		Args:  cli.NoArgs,

 		Run: func(cmd *cobra.Command, args []string) {

-			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())

+			cmd.SetOutput(dockerCli.Err())

+			cmd.HelpFunc()(cmd, args)

 		},

 	}

 	cmd.AddCommand(

@@ -35,6 +35,7 @@ func NewPruneCommand(dockerCli *command.DockerCli) *cobra.Command {

 			fmt.Fprintln(dockerCli.Out(), "Total reclaimed space:", units.HumanSize(float64(spaceReclaimed)))

 			return nil

 		},

+		Tags: map[string]string{"version": "1.25"},

 	}

 	flags := cmd.Flags()

@@ -34,7 +34,7 @@ func newRemoveCommand(dockerCli *command.DockerCli) *cobra.Command {

 	flags := cmd.Flags()

 	flags.BoolVarP(&opts.force, "force", "f", false, "Force the removal of one or more volumes")

-

+	flags.SetAnnotation("force", "version", []string{"1.25"})

 	return cmd

 }

@@ -79,6 +79,8 @@ type Client struct {

 	version string

 	// custom http headers configured by users.

 	customHTTPHeaders map[string]string

+	// manualOverride is set to true when the version was set by users.

+	manualOverride bool

 }

 // NewEnvClient initializes a new API client based on environment variables.

@@ -111,13 +113,19 @@ func NewEnvClient() (*Client, error) {

 	if host == "" {

 		host = DefaultDockerHost

 	}

-

 	version := os.Getenv("DOCKER_API_VERSION")

 	if version == "" {

 		version = DefaultVersion

 	}

-	return NewClient(host, version, client, nil)

+	cli, err := NewClient(host, version, client, nil)

+	if err != nil {

+		return cli, err

+	}

+	if version != "" {

+		cli.manualOverride = true

+	}

+	return cli, nil

 }

 // NewClient initializes a new API client for the given host and API version.

@@ -211,7 +219,10 @@ func (cli *Client) ClientVersion() string {

 // UpdateClientVersion updates the version string associated with this

 // instance of the Client.

 func (cli *Client) UpdateClientVersion(v string) {

-	cli.version = v

+	if !cli.manualOverride {

+		cli.version = v

+	}

+

 }

 // ParseHost verifies that the given host strings is valid.

@@ -20,6 +20,11 @@ type configWrapper struct {

 // It can be associated with a name, but it's not mandatory.

 func (cli *Client) ContainerCreate(ctx context.Context, config *container.Config, hostConfig *container.HostConfig, networkingConfig *network.NetworkingConfig, containerName string) (container.ContainerCreateCreatedBody, error) {

 	var response container.ContainerCreateCreatedBody

+

+	if err := cli.NewVersionError("1.25", "stop timeout"); config != nil && config.StopTimeout != nil && err != nil {

+		return response, err

+	}

+

 	query := url.Values{}

 	if containerName != "" {

 		query.Set("name", containerName)

@@ -10,6 +10,11 @@ import (

 // ContainerExecCreate creates a new exec configuration to run an exec process.

 func (cli *Client) ContainerExecCreate(ctx context.Context, container string, config types.ExecConfig) (types.IDResponse, error) {

 	var response types.IDResponse

+

+	if err := cli.NewVersionError("1.25", "env"); len(config.Env) != 0 && err != nil {

+		return response, err

+	}

+

 	resp, err := cli.post(ctx, "/containers/"+container+"/exec", nil, config, nil)

 	if err != nil {

 		return response, err

@@ -12,6 +12,10 @@ import (

 func (cli *Client) ContainersPrune(ctx context.Context, cfg types.ContainersPruneConfig) (types.ContainersPruneReport, error) {

 	var report types.ContainersPruneReport

+	if err := cli.NewVersionError("1.25", "container prune"); err != nil {

+		return report, err

+	}

+

 	serverResp, err := cli.post(ctx, "/containers/prune", nil, cfg, nil)

 	if err != nil {

 		return report, err

@@ -3,6 +3,8 @@ package client

 import (

 	"errors"

 	"fmt"

+

+	"github.com/docker/docker/api/types/versions"

 )

 // ErrConnectionFailed is an error raised when the connection between the client and the server failed.

@@ -206,3 +208,12 @@ func IsErrPluginPermissionDenied(err error) bool {

 	_, ok := err.(pluginPermissionDenied)

 	return ok

 }

+

+// NewVersionError returns an error if the APIVersion required

+// if less than the current supported version

+func (cli *Client) NewVersionError(APIrequired, feature string) error {

+	if versions.LessThan(cli.version, APIrequired) {

+		return fmt.Errorf("%q requires API version %s, but the Docker server is version %s", feature, APIrequired, cli.version)

+	}

+	return nil

+}

@@ -21,7 +21,7 @@ var headerRegexp = regexp.MustCompile(`\ADocker/.+\s\((.+)\)\z`)

 // The Body in the response implement an io.ReadCloser and it's up to the caller to

 // close it.

 func (cli *Client) ImageBuild(ctx context.Context, buildContext io.Reader, options types.ImageBuildOptions) (types.ImageBuildResponse, error) {

-	query, err := imageBuildOptionsToQuery(options)

+	query, err := cli.imageBuildOptionsToQuery(options)

 	if err != nil {

 		return types.ImageBuildResponse{}, err

 	}

@@ -47,7 +47,7 @@ func (cli *Client) ImageBuild(ctx context.Context, buildContext io.Reader, optio

 	}, nil

 }

-func imageBuildOptionsToQuery(options types.ImageBuildOptions) (url.Values, error) {

+func (cli *Client) imageBuildOptionsToQuery(options types.ImageBuildOptions) (url.Values, error) {

 	query := url.Values{

 		"t":           options.Tags,

 		"securityopt": options.SecurityOpt,

@@ -76,6 +76,9 @@ func imageBuildOptionsToQuery(options types.ImageBuildOptions) (url.Values, erro

 	}

 	if options.Squash {

+		if err := cli.NewVersionError("1.25", "squash"); err != nil {

+			return query, err

+		}

 		query.Set("squash", "1")

 	}

@@ -12,6 +12,10 @@ import (

 func (cli *Client) ImagesPrune(ctx context.Context, cfg types.ImagesPruneConfig) (types.ImagesPruneReport, error) {

 	var report types.ImagesPruneReport

+	if err := cli.NewVersionError("1.25", "image prune"); err != nil {

+		return report, err

+	}

+

 	serverResp, err := cli.post(ctx, "/images/prune", nil, cfg, nil)

 	if err != nil {

 		return report, err

@@ -129,7 +129,7 @@ type SystemAPIClient interface {

 	Info(ctx context.Context) (types.Info, error)

 	RegistryLogin(ctx context.Context, auth types.AuthConfig) (registry.AuthenticateOKBody, error)

 	DiskUsage(ctx context.Context) (types.DiskUsage, error)

-	Ping(ctx context.Context) (bool, error)

+	Ping(ctx context.Context) (types.Ping, error)

 }

 // VolumeAPIClient defines API client methods for the volumes

@@ -1,19 +1,30 @@

 package client

-import "golang.org/x/net/context"

+import (

+	"fmt"

-// Ping pings the server and return the value of the "Docker-Experimental" header

-func (cli *Client) Ping(ctx context.Context) (bool, error) {

-	serverResp, err := cli.get(ctx, "/_ping", nil, nil)

+	"github.com/docker/docker/api/types"

+	"golang.org/x/net/context"

+)

+

+// Ping pings the server and return the value of the "Docker-Experimental" & "API-Version" headers

+func (cli *Client) Ping(ctx context.Context) (types.Ping, error) {

+	var ping types.Ping

+	req, err := cli.buildRequest("GET", fmt.Sprintf("%s/_ping", cli.basePath), nil, nil)

+	if err != nil {

+		return ping, err

+	}

+	serverResp, err := cli.doRequest(ctx, req)

 	if err != nil {

-		return false, err

+		return ping, err

 	}

 	defer ensureReaderClosed(serverResp)

-	exp := serverResp.header.Get("Docker-Experimental")

-	if exp != "true" {

-		return false, nil

+	ping.APIVersion = serverResp.header.Get("API-Version")

+

+	if serverResp.header.Get("Docker-Experimental") == "true" {

+		ping.Experimental = true

 	}

-	return true, nil

+	return ping, nil

 }

@@ -214,6 +214,9 @@ func (cli *Client) addHeaders(req *http.Request, headers headers) *http.Request

 	// Add CLI Config's HTTP Headers BEFORE we set the Docker headers

 	// then the user can't change OUR headers

 	for k, v := range cli.customHTTPHeaders {

+		if versions.LessThan(cli.version, "1.25") && k == "User-Agent" {

+			continue

+		}

 		req.Header.Set(k, v)

 	}

@@ -12,6 +12,10 @@ import (

 func (cli *Client) VolumesPrune(ctx context.Context, cfg types.VolumesPruneConfig) (types.VolumesPruneReport, error) {

 	var report types.VolumesPruneReport

+	if err := cli.NewVersionError("1.25", "volume prune"); err != nil {

+		return report, err

+	}

+

 	serverResp, err := cli.post(ctx, "/volumes/prune", nil, cfg, nil)

 	if err != nil {

 		return report, err

@@ -3,14 +3,17 @@ package client

 import (

 	"net/url"

+	"github.com/docker/docker/api/types/versions"

 	"golang.org/x/net/context"

 )

 // VolumeRemove removes a volume from the docker host.

 func (cli *Client) VolumeRemove(ctx context.Context, volumeID string, force bool) error {

 	query := url.Values{}

-	if force {

-		query.Set("force", "1")

+	if versions.GreaterThanOrEqualTo(cli.version, "1.25") {

+		if force {

+			query.Set("force", "1")

+		}

 	}

 	resp, err := cli.delete(ctx, "/volumes/"+volumeID, query, nil)

 	ensureReaderClosed(resp)

@@ -5,6 +5,7 @@ import (

 	"os"

 	"github.com/Sirupsen/logrus"

+	"github.com/docker/docker/api/types/versions"

 	"github.com/docker/docker/cli"

 	"github.com/docker/docker/cli/command"

 	"github.com/docker/docker/cli/command/commands"

@@ -47,16 +48,15 @@ func newDockerCommand(dockerCli *command.DockerCli) *cobra.Command {

 	cli.SetupRootCommand(cmd)

 	cmd.SetHelpFunc(func(ccmd *cobra.Command, args []string) {

-		var err error

 		if dockerCli.Client() == nil {

 			// flags must be the top-level command flags, not cmd.Flags()

 			opts.Common.SetDefaultOptions(flags)

 			dockerPreRun(opts)

-			err = dockerCli.Initialize(opts)

-		}

-		if err != nil || !dockerCli.HasExperimental() {

-			hideExperimentalFeatures(ccmd)

+			dockerCli.Initialize(opts)

 		}

+

+		hideUnsupportedFeatures(ccmd, dockerCli.Client().ClientVersion(), dockerCli.HasExperimental())

+

 		if err := ccmd.Help(); err != nil {

 			ccmd.Println(err)

 		}

@@ -123,18 +123,29 @@ func dockerPreRun(opts *cliflags.ClientOptions) {

 	}

 }

-func hideExperimentalFeatures(cmd *cobra.Command) {

-	// hide flags

+func hideUnsupportedFeatures(cmd *cobra.Command, clientVersion string, hasExperimental bool) {

 	cmd.Flags().VisitAll(func(f *pflag.Flag) {

+		// hide experimental flags

 		if _, ok := f.Annotations["experimental"]; ok {

 			f.Hidden = true

 		}

+

+		// hide flags not supported by the server

+		if flagVersion, ok := f.Annotations["version"]; ok && len(flagVersion) == 1 && versions.LessThan(clientVersion, flagVersion[0]) {

+			f.Hidden = true

+		}

+

 	})

 	for _, subcmd := range cmd.Commands() {

-		// hide subcommands

+		// hide experimental subcommands

 		if _, ok := subcmd.Tags["experimental"]; ok {

 			subcmd.Hidden = true

 		}

+

+		// hide subcommands not supported by the server

+		if subcmdVersion, ok := subcmd.Tags["version"]; ok && versions.LessThan(clientVersion, subcmdVersion) {

+			subcmd.Hidden = true

+		}

 	}

 }

@@ -480,9 +480,6 @@ func (cli *DaemonCli) initMiddlewares(s *apiserver.Server, cfg *apiserver.Config

 		s.UseMiddleware(c)

 	}

-	u := middleware.NewUserAgentMiddleware(v)

-	s.UseMiddleware(u)

-

 	if err := validateAuthzPlugins(cli.Config.AuthorizationPlugins, cli.d.PluginStore); err != nil {

 		return fmt.Errorf("Error validating authorization plugin: %v", err)

 	}

@@ -162,6 +162,7 @@ This section lists each version from latest to oldest.  Each listing includes a

 * `POST /volumes/prune` prunes unused volumes.

 * `POST /networks/prune` prunes unused networks.

 * Every API response now includes a `Docker-Experimental` header specifying if experimental features are enabled (value can be `true` or `false`).

+* Every API response now includes a `API-Version` header specifying the default API version of the server.