diff --git a/src/Twilio.php b/src/Twilio.php
index a764712..3cf44f4 100644
--- a/src/Twilio.php
+++ b/src/Twilio.php
@@ -81,6 +81,16 @@ protected function sendSmsMessage(TwilioSmsMessage $message, ?string $to): Messa
             'maxPrice',
             'provideFeedback',
             'validityPeriod',
+            'attempt',
+            'contentRetention',
+            'addressRetention',
+            'smartEncoded',
+            'persistentAction',
+            'scheduleType',
+            'sendAt',
+            'sendAsMms',
+            'contentVariables',
+            'riskCheck',
         ]);
 
         if ($message instanceof TwilioMmsMessage) {
diff --git a/src/TwilioSmsMessage.php b/src/TwilioSmsMessage.php
index 5479bb1..b52a44b 100755
--- a/src/TwilioSmsMessage.php
+++ b/src/TwilioSmsMessage.php
@@ -18,6 +18,26 @@ class TwilioSmsMessage extends TwilioMessage
 
     public ?int $validityPeriod = null;
 
+    public ?int $attempt = null;
+
+    public ?string $contentRetention = null;
+
+    public ?string $addressRetention = null;
+
+    public ?bool $smartEncoded = null;
+
+    public ?array $persistentAction = null;
+
+    public ?string $scheduleType = null;
+
+    public ?string $sendAt = null;
+
+    public ?bool $sendAsMms = null;
+
+    public ?string $contentVariables = null;
+
+    public ?string $riskCheck = null;
+
     /**
      * Get the from address of this message.
      */
@@ -111,4 +131,120 @@ public function validityPeriod(int $validityPeriodSeconds): self
 
         return $this;
     }
+
+    /**
+     * Total number of attempts made to send the message (including the current one).
+     */
+    public function attempt(int $attempt): self
+    {
+        $this->attempt = $attempt;
+
+        return $this;
+    }
+
+    /**
+     * Determines if the message content can be stored or redacted based on privacy settings
+     * Possible values:
+     * - retain
+     * - discard
+     */
+    public function contentRetention(string $contentRetention): self
+    {
+        $this->contentRetention = $contentRetention;
+
+        return $this;
+    }
+
+    /**
+     * Determines if the address can be stored or obfuscated based on privacy settings
+     * Possible values:
+     * - retain
+     * - obfuscate
+     */
+    public function addressRetention(string $addressRetention): self
+    {
+        $this->addressRetention = $addressRetention;
+
+        return $this;
+    }
+
+    /**
+     * Whether to detect Unicode characters that have a similar GSM-7 character and replace them
+     */
+    public function smartEncoded(bool $smartEncoded): self
+    {
+        $this->smartEncoded = $smartEncoded;
+
+        return $this;
+    }
+
+    /**
+     * Rich actions for non-SMS/MMS channels. Used for sending location in WhatsApp messages.
+     * @param array<string> $persistentAction
+     * @return $this
+     */
+    public function persistentAction(array $persistentAction): self
+    {
+        $this->persistentAction = $persistentAction;
+
+        return $this;
+    }
+
+    /**
+     * For Messaging Services only: Include this parameter with a value of fixed in conjunction with the send_time parameter in order to schedule a Message.
+     * Possible values:
+     * - fixed
+     */
+    public function scheduleType(string $scheduleType): self
+    {
+        $this->scheduleType = $scheduleType;
+
+        return $this;
+    }
+
+    /**
+     * The time that Twilio will send the message.
+     * Must be in ISO 8601 format.
+     */
+    public function sendAt(string $sendAt): self
+    {
+        $this->sendAt = $sendAt;
+
+        return $this;
+    }
+
+    /**
+     * If set to true, Twilio delivers the message as a single MMS message, regardless of the presence of media.
+     */
+    public function sendAsMms(bool $sendAsMms): self
+    {
+        $this->sendAsMms = $sendAsMms;
+
+        return $this;
+    }
+
+    /**
+     * For Content Editor/API only: Key-value pairs of Template variables and their substitution values.
+     * content_sid parameter must also be provided.
+     * If values are not defined in the content_variables parameter, the Template's default placeholder values are used.
+     */
+    public function contentVariables(string $contentVariables): self
+    {
+        $this->contentVariables = $contentVariables;
+
+        return $this;
+    }
+
+    /**
+     * Include this parameter with a value of "disable" to skip any kind of risk check on the respective message request.
+     * Possible values:
+     * - enable (default)
+     * - disable
+     */
+    public function riskCheck(string $riskCheck): self
+    {
+        $this->riskCheck = $riskCheck;
+
+        return $this;
+    }
 }
diff --git a/tests/Unit/TwilioSmsMessageTest.php b/tests/Unit/TwilioSmsMessageTest.php
index 1e919bc..95a3085 100644
--- a/tests/Unit/TwilioSmsMessageTest.php
+++ b/tests/Unit/TwilioSmsMessageTest.php
@@ -66,6 +66,16 @@ public function it_can_set_optional_parameters()
         $message->maxPrice(0.05);
         $message->provideFeedback(true);
         $message->validityPeriod(120);
+        $message->attempt(3);
+        $message->contentRetention('retain');
+        $message->addressRetention('obfuscate');
+        $message->smartEncoded(true);
+        $message->persistentAction(['action1', 'action2']);
+        $message->scheduleType('fixed');
+        $message->sendAt('2021-01-01 00:00:00');
+        $message->sendAsMms(true);
+        $message->contentVariables('{"name": "John"}');
+        $message->riskCheck('disable');
 
         $this->assertEquals('http://example.com', $message->statusCallback);
         $this->assertEquals('PUT', $message->statusCallbackMethod);
@@ -73,5 +83,15 @@ public function it_can_set_optional_parameters()
         $this->assertEquals(0.05, $message->maxPrice);
         $this->assertEquals(true, $message->provideFeedback);
         $this->assertEquals(120, $message->validityPeriod);
+        $this->assertEquals(3, $message->attempt);
+        $this->assertEquals('retain', $message->contentRetention);
+        $this->assertEquals('obfuscate', $message->addressRetention);
+        $this->assertEquals(true, $message->smartEncoded);
+        $this->assertEquals(['action1', 'action2'], $message->persistentAction);
+        $this->assertEquals('fixed', $message->scheduleType);
+        $this->assertEquals('2021-01-01 00:00:00', $message->sendAt);
+        $this->assertEquals(true, $message->sendAsMms);
+        $this->assertEquals('{"name": "John"}', $message->contentVariables);
+        $this->assertEquals('disable', $message->riskCheck);
     }
 }