diff --git a/services/dns/mgmt/2015-05-04-preview/dns/models.go b/services/dns/mgmt/2015-05-04-preview/dns/models.go
index b6971ba1a65b..43db0e57fb70 100644
--- a/services/dns/mgmt/2015-05-04-preview/dns/models.go
+++ b/services/dns/mgmt/2015-05-04-preview/dns/models.go
@@ -48,6 +48,11 @@ const (
 	TXT RecordType = "TXT"
 )
 
+// PossibleRecordTypeValues returns an array of possible values for the RecordType const type.
+func PossibleRecordTypeValues() [9]RecordType {
+	return [9]RecordType{A, AAAA, CNAME, MX, NS, PTR, SOA, SRV, TXT}
+}
+
 // AaaaRecord an AAAA record.
 type AaaaRecord struct {
 	// Ipv6Address - Gets or sets the IPv6 address of this AAAA record in string notation.
diff --git a/services/dns/mgmt/2016-04-01/dns/models.go b/services/dns/mgmt/2016-04-01/dns/models.go
index ce71cd8a9a03..a9114cbe2799 100644
--- a/services/dns/mgmt/2016-04-01/dns/models.go
+++ b/services/dns/mgmt/2016-04-01/dns/models.go
@@ -125,6 +125,11 @@ const (
 	UseProxy HTTPStatusCode = "UseProxy"
 )
 
+// PossibleHTTPStatusCodeValues returns an array of possible values for the HTTPStatusCode const type.
+func PossibleHTTPStatusCodeValues() [47]HTTPStatusCode {
+	return [47]HTTPStatusCode{Accepted, Ambiguous, BadGateway, BadRequest, Conflict, Continue, Created, ExpectationFailed, Forbidden, Found, GatewayTimeout, Gone, HTTPVersionNotSupported, InternalServerError, LengthRequired, MethodNotAllowed, Moved, MovedPermanently, MultipleChoices, NoContent, NonAuthoritativeInformation, NotAcceptable, NotFound, NotImplemented, NotModified, OK, PartialContent, PaymentRequired, PreconditionFailed, ProxyAuthenticationRequired, Redirect, RedirectKeepVerb, RedirectMethod, RequestedRangeNotSatisfiable, RequestEntityTooLarge, RequestTimeout, RequestURITooLong, ResetContent, SeeOther, ServiceUnavailable, SwitchingProtocols, TemporaryRedirect, Unauthorized, UnsupportedMediaType, Unused, UpgradeRequired, UseProxy}
+}
+
 // OperationStatus enumerates the values for operation status.
 type OperationStatus string
 
@@ -137,6 +142,11 @@ const (
 	Succeeded OperationStatus = "Succeeded"
 )
 
+// PossibleOperationStatusValues returns an array of possible values for the OperationStatus const type.
+func PossibleOperationStatusValues() [3]OperationStatus {
+	return [3]OperationStatus{Failed, InProgress, Succeeded}
+}
+
 // RecordType enumerates the values for record type.
 type RecordType string
 
@@ -161,6 +171,11 @@ const (
 	TXT RecordType = "TXT"
 )
 
+// PossibleRecordTypeValues returns an array of possible values for the RecordType const type.
+func PossibleRecordTypeValues() [9]RecordType {
+	return [9]RecordType{A, AAAA, CNAME, MX, NS, PTR, SOA, SRV, TXT}
+}
+
 // AaaaRecord an AAAA record.
 type AaaaRecord struct {
 	// Ipv6Address - The IPv6 address of this AAAA record.
diff --git a/services/dns/mgmt/2017-09-01/dns/models.go b/services/dns/mgmt/2017-09-01/dns/models.go
index e5594bb73942..b08900ce4d9c 100644
--- a/services/dns/mgmt/2017-09-01/dns/models.go
+++ b/services/dns/mgmt/2017-09-01/dns/models.go
@@ -51,6 +51,11 @@ const (
 	TXT RecordType = "TXT"
 )
 
+// PossibleRecordTypeValues returns an array of possible values for the RecordType const type.
+func PossibleRecordTypeValues() [10]RecordType {
+	return [10]RecordType{A, AAAA, CAA, CNAME, MX, NS, PTR, SOA, SRV, TXT}
+}
+
 // AaaaRecord an AAAA record.
 type AaaaRecord struct {
 	// Ipv6Address - The IPv6 address of this AAAA record.
diff --git a/services/dns/mgmt/2017-10-01/dns/models.go b/services/dns/mgmt/2017-10-01/dns/models.go
index e5594bb73942..edf4978dc07e 100644
--- a/services/dns/mgmt/2017-10-01/dns/models.go
+++ b/services/dns/mgmt/2017-10-01/dns/models.go
@@ -51,6 +51,11 @@ const (
 	TXT RecordType = "TXT"
 )
 
+// PossibleRecordTypeValues returns an array of possible values for the RecordType const type.
+func PossibleRecordTypeValues() [10]RecordType {
+	return [10]RecordType{A, AAAA, CAA, CNAME, MX, NS, PTR, SOA, SRV, TXT}
+}
+
 // AaaaRecord an AAAA record.
 type AaaaRecord struct {
 	// Ipv6Address - The IPv6 address of this AAAA record.
@@ -735,3 +740,18 @@ func (future ZonesDeleteFuture) Result(client ZonesClient) (ar autorest.Response
 	}
 	return
 }
+
+// ZoneUpdate describes a request to update a DNS zone.
+type ZoneUpdate struct {
+	// Tags - Resource tags.
+	Tags map[string]*string `json:"tags"`
+}
+
+// MarshalJSON is the custom marshaler for ZoneUpdate.
+func (zu ZoneUpdate) MarshalJSON() ([]byte, error) {
+	objectMap := make(map[string]interface{})
+	if zu.Tags != nil {
+		objectMap["tags"] = zu.Tags
+	}
+	return json.Marshal(objectMap)
+}
diff --git a/services/dns/mgmt/2017-10-01/dns/zones.go b/services/dns/mgmt/2017-10-01/dns/zones.go
index 9e8d2ce55c62..3cd53111f548 100644
--- a/services/dns/mgmt/2017-10-01/dns/zones.go
+++ b/services/dns/mgmt/2017-10-01/dns/zones.go
@@ -458,7 +458,7 @@ func (client ZonesClient) ListByResourceGroupComplete(ctx context.Context, resou
 // dot). parameters is parameters supplied to the Update operation. ifMatch is the etag of the DNS zone. Omit this
 // value to always overwrite the current zone. Specify the last-seen etag value to prevent accidentally
 // overwritting any concurrent changes.
-func (client ZonesClient) Update(ctx context.Context, resourceGroupName string, zoneName string, parameters Zone, ifMatch string) (result Zone, err error) {
+func (client ZonesClient) Update(ctx context.Context, resourceGroupName string, zoneName string, parameters ZoneUpdate, ifMatch string) (result Zone, err error) {
 	req, err := client.UpdatePreparer(ctx, resourceGroupName, zoneName, parameters, ifMatch)
 	if err != nil {
 		err = autorest.NewErrorWithError(err, "dns.ZonesClient", "Update", nil, "Failure preparing request")
@@ -481,7 +481,7 @@ func (client ZonesClient) Update(ctx context.Context, resourceGroupName string,
 }
 
 // UpdatePreparer prepares the Update request.
-func (client ZonesClient) UpdatePreparer(ctx context.Context, resourceGroupName string, zoneName string, parameters Zone, ifMatch string) (*http.Request, error) {
+func (client ZonesClient) UpdatePreparer(ctx context.Context, resourceGroupName string, zoneName string, parameters ZoneUpdate, ifMatch string) (*http.Request, error) {
 	pathParameters := map[string]interface{}{
 		"resourceGroupName": autorest.Encode("path", resourceGroupName),
 		"subscriptionId":    autorest.Encode("path", client.SubscriptionID),