diff --git a/cli/command/service/opts.go b/cli/command/service/opts.go
index c51d37c1de..ce9f39c842 100644
--- a/cli/command/service/opts.go
+++ b/cli/command/service/opts.go
@@ -331,12 +331,14 @@ func (c *credentialSpecOpt) Set(value string) error {
 	c.source = value
 	c.value = &swarm.CredentialSpec{}
 	switch {
+	case strings.HasPrefix(value, "config://"):
+		c.value.Config = strings.TrimPrefix(value, "config://")
 	case strings.HasPrefix(value, "file://"):
 		c.value.File = strings.TrimPrefix(value, "file://")
 	case strings.HasPrefix(value, "registry://"):
 		c.value.Registry = strings.TrimPrefix(value, "registry://")
 	default:
-		return errors.New("Invalid credential spec - value must be prefixed file:// or registry:// followed by a value")
+		return errors.New(`invalid credential spec: value must be prefixed with "config://", "file://", or "registry://"`)
 	}
 
 	return nil
diff --git a/cli/command/service/opts_test.go b/cli/command/service/opts_test.go
index 9493a82303..9f26daa3bf 100644
--- a/cli/command/service/opts_test.go
+++ b/cli/command/service/opts_test.go
@@ -14,6 +14,61 @@ import (
 	is "gotest.tools/assert/cmp"
 )
 
+func TestCredentialSpecOpt(t *testing.T) {
+	tests := []struct {
+		name        string
+		in          string
+		value       swarm.CredentialSpec
+		expectedErr string
+	}{
+		{
+			name:        "empty",
+			in:          "",
+			value:       swarm.CredentialSpec{},
+			expectedErr: `invalid credential spec: value must be prefixed with "config://", "file://", or "registry://"`,
+		},
+		{
+			name:        "no-prefix",
+			in:          "noprefix",
+			value:       swarm.CredentialSpec{},
+			expectedErr: `invalid credential spec: value must be prefixed with "config://", "file://", or "registry://"`,
+		},
+		{
+			name:  "config",
+			in:    "config://0bt9dmxjvjiqermk6xrop3ekq",
+			value: swarm.CredentialSpec{Config: "0bt9dmxjvjiqermk6xrop3ekq"},
+		},
+		{
+			name:  "file",
+			in:    "file://somefile.json",
+			value: swarm.CredentialSpec{File: "somefile.json"},
+		},
+		{
+			name:  "registry",
+			in:    "registry://testing",
+			value: swarm.CredentialSpec{Registry: "testing"},
+		},
+	}
+
+	for _, tc := range tests {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			var cs credentialSpecOpt
+
+			err := cs.Set(tc.in)
+
+			if tc.expectedErr != "" {
+				assert.Error(t, err, tc.expectedErr)
+			} else {
+				assert.NilError(t, err)
+			}
+
+			assert.Equal(t, cs.String(), tc.in)
+			assert.DeepEqual(t, cs.Value(), &tc.value)
+		})
+	}
+}
+
 func TestMemBytesString(t *testing.T) {
 	var mem opts.MemBytes = 1048576
 	assert.Check(t, is.Equal("1MiB", mem.String()))
diff --git a/cli/compose/convert/service.go b/cli/compose/convert/service.go
index 21f4850c87..0fe40bf3a7 100644
--- a/cli/compose/convert/service.go
+++ b/cli/compose/convert/service.go
@@ -600,11 +600,26 @@ func convertDNSConfig(DNS []string, DNSSearch []string) (*swarm.DNSConfig, error
 }
 
 func convertCredentialSpec(spec composetypes.CredentialSpecConfig) (*swarm.CredentialSpec, error) {
-	if spec.File == "" && spec.Registry == "" {
-		return nil, nil
+	var o []string
+
+	// Config was added in API v1.40
+	if spec.Config != "" {
+		o = append(o, `"Config"`)
 	}
-	if spec.File != "" && spec.Registry != "" {
-		return nil, errors.New("Invalid credential spec - must provide one of `File` or `Registry`")
+	if spec.File != "" {
+		o = append(o, `"File"`)
+	}
+	if spec.Registry != "" {
+		o = append(o, `"Registry"`)
+	}
+	l := len(o)
+	switch {
+	case l == 0:
+		return nil, nil
+	case l == 2:
+		return nil, errors.Errorf("invalid credential spec: cannot specify both %s and %s", o[0], o[1])
+	case l > 2:
+		return nil, errors.Errorf("invalid credential spec: cannot specify both %s, and %s", strings.Join(o[:l-1], ", "), o[l-1])
 	}
 	swarmCredSpec := swarm.CredentialSpec(spec)
 	return &swarmCredSpec, nil
diff --git a/cli/compose/convert/service_test.go b/cli/compose/convert/service_test.go
index d281e0e452..f275fb874c 100644
--- a/cli/compose/convert/service_test.go
+++ b/cli/compose/convert/service_test.go
@@ -314,30 +314,65 @@ func TestConvertDNSConfigSearch(t *testing.T) {
 }
 
 func TestConvertCredentialSpec(t *testing.T) {
-	swarmSpec, err := convertCredentialSpec(composetypes.CredentialSpecConfig{})
-	assert.NilError(t, err)
-	assert.Check(t, is.Nil(swarmSpec))
+	tests := []struct {
+		name        string
+		in          composetypes.CredentialSpecConfig
+		out         *swarm.CredentialSpec
+		expectedErr string
+	}{
+		{
+			name: "empty",
+		},
+		{
+			name:        "config-and-file",
+			in:          composetypes.CredentialSpecConfig{Config: "0bt9dmxjvjiqermk6xrop3ekq", File: "somefile.json"},
+			expectedErr: `invalid credential spec: cannot specify both "Config" and "File"`,
+		},
+		{
+			name:        "config-and-registry",
+			in:          composetypes.CredentialSpecConfig{Config: "0bt9dmxjvjiqermk6xrop3ekq", Registry: "testing"},
+			expectedErr: `invalid credential spec: cannot specify both "Config" and "Registry"`,
+		},
+		{
+			name:        "file-and-registry",
+			in:          composetypes.CredentialSpecConfig{File: "somefile.json", Registry: "testing"},
+			expectedErr: `invalid credential spec: cannot specify both "File" and "Registry"`,
+		},
+		{
+			name:        "config-and-file-and-registry",
+			in:          composetypes.CredentialSpecConfig{Config: "0bt9dmxjvjiqermk6xrop3ekq", File: "somefile.json", Registry: "testing"},
+			expectedErr: `invalid credential spec: cannot specify both "Config", "File", and "Registry"`,
+		},
+		{
+			name: "config",
+			in:   composetypes.CredentialSpecConfig{Config: "0bt9dmxjvjiqermk6xrop3ekq"},
+			out:  &swarm.CredentialSpec{Config: "0bt9dmxjvjiqermk6xrop3ekq"},
+		},
+		{
+			name: "file",
+			in:   composetypes.CredentialSpecConfig{File: "somefile.json"},
+			out:  &swarm.CredentialSpec{File: "somefile.json"},
+		},
+		{
+			name: "registry",
+			in:   composetypes.CredentialSpecConfig{Registry: "testing"},
+			out:  &swarm.CredentialSpec{Registry: "testing"},
+		},
+	}
 
-	swarmSpec, err = convertCredentialSpec(composetypes.CredentialSpecConfig{
-		File: "/foo",
-	})
-	assert.NilError(t, err)
-	assert.Check(t, is.Equal(swarmSpec.File, "/foo"))
-	assert.Check(t, is.Equal(swarmSpec.Registry, ""))
+	for _, tc := range tests {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			swarmSpec, err := convertCredentialSpec(tc.in)
 
-	swarmSpec, err = convertCredentialSpec(composetypes.CredentialSpecConfig{
-		Registry: "foo",
-	})
-	assert.NilError(t, err)
-	assert.Check(t, is.Equal(swarmSpec.File, ""))
-	assert.Check(t, is.Equal(swarmSpec.Registry, "foo"))
-
-	swarmSpec, err = convertCredentialSpec(composetypes.CredentialSpecConfig{
-		File:     "/asdf",
-		Registry: "foo",
-	})
-	assert.Check(t, is.ErrorContains(err, ""))
-	assert.Check(t, is.Nil(swarmSpec))
+			if tc.expectedErr != "" {
+				assert.Error(t, err, tc.expectedErr)
+			} else {
+				assert.NilError(t, err)
+			}
+			assert.DeepEqual(t, swarmSpec, tc.out)
+		})
+	}
 }
 
 func TestConvertUpdateConfigOrder(t *testing.T) {
diff --git a/cli/compose/loader/loader_test.go b/cli/compose/loader/loader_test.go
index f78eb2f1fe..a5933cc31c 100644
--- a/cli/compose/loader/loader_test.go
+++ b/cli/compose/loader/loader_test.go
@@ -295,6 +295,20 @@ configs:
 	assert.Assert(t, is.Len(actual.Configs, 1))
 }
 
+func TestLoadV38(t *testing.T) {
+	actual, err := loadYAML(`
+version: "3.8"
+services:
+  foo:
+    image: busybox
+    credential_spec:
+      config: "0bt9dmxjvjiqermk6xrop3ekq"
+`)
+	assert.NilError(t, err)
+	assert.Assert(t, is.Len(actual.Services, 1))
+	assert.Check(t, is.Equal(actual.Services[0].CredentialSpec.Config, "0bt9dmxjvjiqermk6xrop3ekq"))
+}
+
 func TestParseAndLoad(t *testing.T) {
 	actual, err := loadYAML(sampleYAML)
 	assert.NilError(t, err)
diff --git a/cli/compose/schema/bindata.go b/cli/compose/schema/bindata.go
index ccecb08cbc..581e9d502d 100644
--- a/cli/compose/schema/bindata.go
+++ b/cli/compose/schema/bindata.go
@@ -510,45 +510,45 @@ bnBpPlHfjORjkTRf1wyAwiYqMXd9/G6313QfoXs6/sbZ66r6e179PwAA//8ZL3SpvkUAAA==
 
 	"/data/config_schema_v3.8.json": {
 		local:   "data/config_schema_v3.8.json",
-		size:    18204,
+		size:    18246,
 		modtime: 1518458244,
 		compressed: `
 H4sIAAAAAAAC/+xcS4/juBG++1cI2r1tPwbIIkjmlmNOyTkNj0BTZZvbFMktUp72DvzfAz1bokiRtuXu
-3qQDBDstFR9FVn38qljyj1WSpD9ruoeCpF+TdG+M+vr4+JuW4r55+iBx95gj2Zr7L78+Ns9+Su+qdiyv
-mlAptmyXNW+yw18e/vZQNW9EzFFBJSQ3vwE1zTOE30uGUDV+Sg+AmkmRru9W1TuFUgEaBjr9mlSTS5Je
-pHsw6FYbZGKX1o9PdQ9JkmrAA6ODHvqp/vT42v9jL3Zn9zqYbP1cEWMAxb+nc6tff3si93/84/4/X+7/
-/pDdr3/5efS6Wl+EbTN8DlsmmGFS9OOnveSp/depH5jkeS1M+GjsLeEaxjoLMN8lPod07sXeSed2fIfO
-Y3UOkpdFcAc7qXdSphl+mf3TQBFM2GQbqXez2Gr4ZRRuUCOkcCf1Tgo3w1+n8KpT2j3H9NvLffXfU93n
-bH9NL4P51UqMMM+1nC7M8a9nv6CelcxBcXmsZ+5es0agAGHSfpmSJN2UjOf2qksB/6q6eBo8TJIfNrwP
-+qnfj/7yG0X/3qNL/55KYeDF1ErND90sgaTPgFvGIbYFwcbSPUvGmTaZxCxn1Djbc7IBflUPlNA9ZFuU
-RbCXbdZoop0ddQgeqbkhuIPoldX7ItPsj9G6PqVMGNgBpnd92/XJajvpLOyYtk9X/1uvHB2mlKiM5PlI
-CYJIjtWMmIFCu/VL0lKw30v4ZytisAS73xylWr7jHcpSZYpg5YXza59SWRRELOWa5+gRsfKTQ2Lk7+0Y
-w1f9aKNpebRJIqzSARcBuAkDTmXpskQaix/n+lGSpCXL44V35wgXMh/PW5TFBjA9TYQnTjr6e71yvbF2
-3xAmADNBCgjaMUIOwjDCM62A+mzGsWlz25VGwnyKsGPa4NEpu/IgVRxKDbXMQYHIddaEQ+fjeJpDHxst
-ijm5mDufmm6qE6qaW2o1zDQQpPsL28uCMBFjISAMHpVkDSZ+OLADcch6azt7GUAcGEpRdIgfxxMG7V+U
-1HA90vandqv4XQ8Qa8tjthILUk22G9vrJVPLGy7gUIeKXxOecSaelzdxeDFIsr3U5hIqlu6BcLOne6DP
-M82HUqPWUpsYI2cF2YWFBBufJRspORAxFlI02I+WnJg2NzMneDGBTRfdykG3crerRH32OwmIIkOJHNkB
-MJbvSvUax7kO/RDRCAa+I9FvD03cO+Oj9b84nxJs13luP7GPxNjD7XVXCkIrpo2gdcii2jgkm9CRV9mJ
-sI7F/YvCo/PD0qitC+YugiTXR2TjrSyO1HbbzhnRoK+LMwcodPg10iZcbf8629bT1NtnfFQZ6GrInjl3
-TmQd5tO3DHrVOCYYY0WNEEMHUxLNm4Rprzj1Sh+awaeRm73dUY1uE+7NoFRcsNflQNwNVLnhTO8hP6cN
-SiOp5HGO4cxqxTvDTOh3EdNTyA6Mw87S2EVjEEieScGPEZLaEAwmTDTQEpk5ZlKZxTmmOwP2avV9Amw8
-Ievu4DNL8v+TJdFHTc1l3FqbnIlMKhBB39BGqmyHhEKmAJl0LsUIYPMSm9Bg0o1mO0F4yM1MobYXphSM
-CTt7yVnB/E7jTBMF+VrD1dwUbYaeRUH2TIQwHyBERAZ7gmccHbVjbj3n0yqSA42rAOr+7tqJrJ3yZ1Ev
-exprL/txO1Wpg0FcLSN0FnG0O66z/xwIPdqjWnx9EY63I0Vi561RP5oRjK8INdMGBD3GD7Rhk3uVc+Ou
-uKirliI7fyrGHZtE+2pb6fAmqghJpfJszZVq9EfK7bXoOJw/OLWRcyaOLZhgRVmkX5Mvvog1fmVuTO2t
-HNAMofdh73eJz9XJnjOcs+XTfO3HuK7izOIUK1U7V1ExFA1WqcxXd4QqL5gmG+syypm3FQbw4CZYYYaG
-YJBZ90Mddx1SLNAf8xbFsAJkaS6lpwTN+QTXrmEbFMp09zFzJjSQtC3oqTehLu0SNJMYPgIir+/BosgL
-guKMEh0iiFck+VFyviH0OWsLrha6u1UECefAmS5i2G2aAyfHiyynudAijJcIGaERVyLtXglmJF4+ZEFe
-sm7YWiTgt42fYg6+MUHU54zNLxvPuN8y1KZJQ0jV/jWG/wWvukuVEwOfJvFpEsMMXR0b6KXMwZkEWKam
-UJWx9xVpAYUMV45cm/KfFKzoiib4LiA/ygI4pHcgABnNRtbgOXKmsje6RbneshvuITlrQswlzJtK0cwj
-BnmuhLoKdyoiXiijo6D1OxO5/H4+zVpgtRUnFCxqdu1Ca4OECXN2rYK9LAphCwiCwqxbTnNGM3mj5RLy
-CoHk73Bl5LK2jphWhD0TNpN1ZSQvMZsrvnFwAtVcJDBtMAkpx/vu2G//Pvv3t4otKYKBfmRXDWXIhubt
-J31us2FBiE8PhJcRtycX1Zv4sg4RjU/OT65Ce9qJLRDaxdR/RRUgtVKZVMvfgISLjNbh/DtTpFgKm6NL
-slJnqPERULfcCE+C+8aou9yR29Vmenb1qU9l3fVrtY7eYq9jLDf/OqtmX1u60m/EGEL3UZm6MxMmb5D4
-nCT6nZDWSn0i2hmI9me3/49nq+3XqMEvHmup8AekV1hoxDciH2D/l9jW/zm3rOJVTgxkM+q8gS1PmIfT
-llupT1te2pY/iBVYJU0Da5herc1tUHTd9Wp4k9ZPwxZz/O6GLwr1Tsp3EWwN2u7NvOYLgsjDLzNsf+77
-iBvR5AWKSd17aiWoVn3pqP2zAX7o6dpPfkSg0lMcJ1e/P8blQ80PAKxH62OJNN8uDVB7HZW8cP20gF28
-1H3i76mnHEf4q+r/p9V/AwAA//9tFzTmHEcAAA==
+3qQDBDstFR/15FfFkn+skiT9WdM9FCT9mqR7Y9TXx8fftBT3zdMHibvHHMnW3H/59bF59lN6V41jeTWE
+SrFlu6x5kx3+8vC3h2p4Q2KOCioiufkNqGmeIfxeMoRq8FN6ANRMinR9t6reKZQK0DDQ6dek2lyS9CTd
+g8G02iATu7R+fKpnSJJUAx4YHczQb/Wnx9f5H3uyO3vWwWbr54oYAyj+Pd1b/frbE7n/4x/3//ly//eH
+7H79y8+j15V8EbbN8jlsmWCGSdGvn/aUp/Zfp35hkuc1MeGjtbeEaxjzLMB8l/gc4rkneyee2/UdPI/Z
+OUheFkENdlTvxEyz/DL600ARTNhkG6p3s9hq+WUYbqJGiOGO6p0Ybpa/juFVx7R7j+m3l/vqv6d6ztn5
+mlkG+6uZGMU8lzhdMccvz16gHknmoLg81jt3y6whKECYtBdTkqSbkvHclroU8K9qiqfBwyT5YYf3wTz1
++9FffqPo33t46d9TKQy8mJqp+aUbEUj6DLhlHGJHEGws3SMyzrTJJGY5o8Y5npMN8KtmoITuIduiLIKz
+bLOGE+2cqIvgkZwbgjuIlqzeF5lmf4zk+pQyYWAHmN71Y9cna+xksrBj2j5d/W+9ckyYUqIykucjJggi
+OVY7YgYK7eYvSUvBfi/hny2JwRLseXOUavmJdyhLlSmClRfOyz6lsiiIWMo1z+EjQvKTQ2Lk7+0aw1f9
+aqNtebhJIqzSES4C4SYccCpLlyXS2Phxrh8lSVqyPJ54dw5xIfPxvkVZbADT04R44qSjv9cr1xtL+4Yw
+AZgJUkDQjhFyEIYRnmkF1GczDqXNqas1wQjxpJEHQoqwY9rg0Um78sS0uHg2lEcOCkSusyZxOj/ipzn0
+WdSi0SkXcydZM011llV7S62BmQaCdH/heFkQJmJsCYTBo5KsiZ4fLiyCOGS9tZ0tBhAHhlIU3dkQhygG
+41+U1HB9TO7P95bxuz6UrG3PkliQarPd2l4vmVreUIBDHiokTnjGmXhe3sThxSDJ9lKbS0BbugfCzZ7u
+gT7PDB9SjUZLbWKMnBVkFyYSbHzqbKTkQMSYSNHgPFpyYtoqzhzhxVA3XVSVg2nlbleR+ux3kjpFJh05
+sgNgLDKW6jXjc8GDECQJpsgj0m8PTYY846P1vzifQnHXyW8/sY/E2MPtVSsFoRUmR9A6ZFFtxpJNgMsr
+7YRYx8b9ixKp8xPYKNUFqxxBOOyDvPFWFgd/O7VzRjTo6zLSQRQ6/BppE66xf50d6xnqnTM+/wxMNcTZ
+nDs3sg4j71umx2qcPYxjRR0hhg6mJJo3Sehe49QrfGgWn+Z4trqjBt0mMZyJUnFpYVctcQ9Q5YYzvYf8
+nDEojaSSxzmGs/4V7wwzSeJFSE8hOzAOO4tjF4xBIHkmBT9GUGpDMFha0UBLZOaYSWUWx5juWtmr1fel
+svGGrFuGz3rK/089RR81NZdha21yJjKpQAR9Qxupsh0SCpkCZNIpilGAzUtsUoPJNJrtBOEhNzOF2l5Y
+UjAm7OwlZwXzO42zoBTEaw1Wc0O0GXgWFbJnMoT5BCEiM9gTPOPoqB1z6zmfVpEYaNwvUM93125k7aQ/
+C3rZ21h70Y/bqUodTOJqGqGziKPdcfH954jQIx3V5OuL4ni7UmTsvHXUj0YE44KxZtqAoMf4hTZscgNz
+bt4Vl3XVVGTnL8W4c5NoX217It6EFSGpVB7VXMlGf6TcnosOw/mTUztyzuSxBROsKIv0a/LFl7HGS+bG
+0N6qAc0Ael/s/S7xuTrZc4Zztnya7xIZd2Cc2cZilWrnei+GpMF+lvk+kFCPBtNkY11GOeu2wgAe3AAr
+jNAQDDLrfqjDrkOIBfpj3qIYVoAszaXwlKA5H+Da3W6DlpruPmbOhAaUtgU99SbUlV2CZhKDR0Dk9T1Y
+FHhBUJxRokMA8YoiP0rON4Q+Z6/3skvc8iqChHPgTBcx6DbNgZPjRZbTXGgRxkuEjNCIK5FWV4IZiZcv
+WZCXrFu2Jgn4beOnmINvTRD1OWPjy8Yz7rcMtWnKEFK1f43D/4JX3aXKiYFPk/g0iWGFrs4N9FLm4CwC
+LNN9qMrY+4q0gEKGO0euLflPGlZ0BRN8F5AfRQAO6h0IQEazkTV4jpwp7Y1uUa637AZ7SM6aFHOhNqdm
+HzGR58pQV8WdCogXyuio0PqdiVx+Px9mLSBtxQkFC5pdK2htkDBhzu5VsMWiELaAICjMuuW0ZjRTN1qu
+IK8QSP4OV0Yua+uAaQXYM2EjWVdF8hKzueJrCGegmssEpgMmKeVY7w59+/Xs12+VW1IEA/3Krm7LkA3N
+20/63FbDgiE+PRBeRtyeXNRv4qs6RAw+OT/OCum0I1sgtYvp/4pqQGqpMqmWvwEJNxmtw/V3pkixVGyO
+bslKnanGR4i65UZ4Ctw3jrrLHbldb6ZHq099Keuul9U6WsVex1hu/3VVzb62dJXfiDGE7qMqdWcWTN6g
+8Dkp9DtDWkv1GdHOiGh/dvv/eLbafrca/Daypgp/anqFhUZ8I/IB9L+EWv/n3LLKVzkxkM2w8wa2PEEe
+TltuqT5teWlb/iBWYLU0DaxherU2p6DovuvV8Cat34ZN5viFDl8W6t2U7yLYWrTVzTznCwaRh19m0P7c
+9xE3gskLNJO6dWoVqFZ966j9AwP+0NONn/zcQMWnOE6ufn+M24eanwpYj+RjkTTfLg2i9jqqeOH6EQK7
+ean7MQBPP+U4w19V/z+t/hsAAP//Fd/bF0ZHAAA=
 `,
 	},
 
diff --git a/cli/compose/schema/data/config_schema_v3.8.json b/cli/compose/schema/data/config_schema_v3.8.json
index 670780905b..059c0bcf76 100644
--- a/cli/compose/schema/data/config_schema_v3.8.json
+++ b/cli/compose/schema/data/config_schema_v3.8.json
@@ -125,6 +125,7 @@
         "credential_spec": {
           "type": "object",
           "properties": {
+            "config": {"type": "string"},
             "file": {"type": "string"},
             "registry": {"type": "string"}
           },
diff --git a/cli/compose/schema/schema_test.go b/cli/compose/schema/schema_test.go
index 9b29b138b3..10c40bba72 100644
--- a/cli/compose/schema/schema_test.go
+++ b/cli/compose/schema/schema_test.go
@@ -92,7 +92,7 @@ func TestValidateCredentialSpecs(t *testing.T) {
 		{version: "3.5", expectedErr: "config"},
 		{version: "3.6", expectedErr: "config"},
 		{version: "3.7", expectedErr: "config"},
-		{version: "3.8", expectedErr: "something"},
+		{version: "3.8"},
 	}
 
 	for _, tc := range tests {
@@ -104,7 +104,7 @@ func TestValidateCredentialSpecs(t *testing.T) {
 					"foo": dict{
 						"image": "busybox",
 						"credential_spec": dict{
-							tc.expectedErr: "foobar",
+							"config": "foobar",
 						},
 					},
 				},
diff --git a/cli/compose/types/types.go b/cli/compose/types/types.go
index 0895a4d04d..d77c1b63dc 100644
--- a/cli/compose/types/types.go
+++ b/cli/compose/types/types.go
@@ -500,8 +500,7 @@ func (e External) MarshalJSON() ([]byte, error) {
 
 // CredentialSpecConfig for credential spec on Windows
 type CredentialSpecConfig struct {
-	// @TODO Config is not yet in use
-	Config   string `yaml:"-" json:"-"` // Config was added in API v1.40
+	Config   string `yaml:",omitempty" json:"config,omitempty"` // Config was added in API v1.40
 	File     string `yaml:",omitempty" json:"file,omitempty"`
 	Registry string `yaml:",omitempty" json:"registry,omitempty"`
 }