diff --git a/domains.go b/domains.go
index ad0ccdf..4b0aef1 100644
--- a/domains.go
+++ b/domains.go
@@ -46,8 +46,9 @@ type ListDomainsResponse struct {
 }
 
 type UpdateDomainRequest struct {
-	OpenTracking  bool `json:"open_tracking,omitempty"`
-	ClickTracking bool `json:"click_tracking,omitempty"`
+	OpenTracking  bool   `json:"open_tracking,omitempty"`
+	ClickTracking bool   `json:"click_tracking,omitempty"`
+	Tls           string `json:"tls,omitempty"`
 }
 
 type Domain struct {
diff --git a/domains_test.go b/domains_test.go
index 8e4144b..6cd2b6d 100644
--- a/domains_test.go
+++ b/domains_test.go
@@ -229,6 +229,7 @@ func TestUpdateDomain(t *testing.T) {
 
 	params := &UpdateDomainRequest{
 		OpenTracking: true,
+		Tls:          "opportunistic",
 	}
 	updated, err := client.Domains.Update("d91cd9bd-1176-453e-8fc1-35364d380206", params)
 	if err != nil {
diff --git a/examples/domains.go b/examples/domains.go
index 12a84c7..06bf9ad 100644
--- a/examples/domains.go
+++ b/examples/domains.go
@@ -40,6 +40,7 @@ func domainsExample() {
 	updateDomainParams := &resend.UpdateDomainRequest{
 		OpenTracking:  true,
 		ClickTracking: true,
+		Tls:           "opportunistic",
 	}
 
 	updated, err := client.Domains.UpdateWithContext(ctx, domain.Id, updateDomainParams)
diff --git a/resend.go b/resend.go
index d40c45a..b3b2284 100644
--- a/resend.go
+++ b/resend.go
@@ -12,7 +12,7 @@ import (
 )
 
 const (
-	version     = "2.5.0"
+	version     = "2.6.0"
 	userAgent   = "resend-go/" + version
 	contentType = "application/json"
 )