diff --git a/src/ChannelClient.php b/src/ChannelClient.php
index 855ad95..f4aaa3e 100644
--- a/src/ChannelClient.php
+++ b/src/ChannelClient.php
@@ -18,7 +18,7 @@ public function __construct(string $landlord_id, string $channel_id, string $dis
 
 	protected function authQuery(RequestInterface $request): array{
 		$timestamp = time();
-		$auth = $this->generateAuth((string)$timestamp);
+		$auth = $this->generateAuth((string)$request->getBody(), (string)$timestamp);
 
 		return [
 			'auth' => $auth,
@@ -27,7 +27,7 @@ protected function authQuery(RequestInterface $request): array{
 		];
 	}
 
-	private function generateAuth(string $timestamp): string{
-		return hash_hmac('sha256', $timestamp, $this->display_key) ?: '';
+	private function generateAuth(string $json, string $timestamp): string{
+		return hash_hmac('sha256', $json.$timestamp, $this->display_key) ?: '';
 	}
 }
diff --git a/src/Models/EnquiryCreation.php b/src/Models/EnquiryCreation.php
new file mode 100644
index 0000000..bb31103
--- /dev/null
+++ b/src/Models/EnquiryCreation.php
@@ -0,0 +1,292 @@
+<?php
+namespace SturentsLib\Api\Models;
+
+/**
+ * ** This file was generated automatically, you might want to avoid editing it **
+ */
+class EnquiryCreation extends SwaggerModel
+{
+	/**
+	 * Plain (non-hashed) house id
+	 * @var int
+	 * @required
+	 */
+	protected $property_id;
+
+	/**
+	 * Hashed availability id
+	 * @var string
+	 * @required
+	 */
+	protected $contract_id;
+
+	/**
+	 * @var string
+	 * @required
+	 */
+	protected $first_name;
+
+	/**
+	 * @var string
+	 * @required
+	 */
+	protected $last_name;
+
+	/**
+	 * @var string
+	 * @required
+	 */
+	protected $email;
+
+	/**
+	 * @var string
+	 * @required
+	 */
+	protected $phone;
+
+	/**
+	 * @var string
+	 * @required
+	 */
+	protected $tenant_type;
+
+	/**
+	 * @var string
+	 * @required
+	 */
+	protected $enquiry_method;
+
+	/**
+	 * @var string
+	 * @required
+	 */
+	protected $enquiry_type;
+
+	/**
+	 * Optional free-text message; used as the enquiry subject if provided,
+	 * otherwise a label derived from enquiry_type is used
+	 *
+	 * @var string
+	 */
+	protected $message = '';
+
+
+	/**
+	 * @return int
+	 */
+	public function getPropertyId()
+	{
+		return $this->property_id;
+	}
+
+
+	/**
+	 * @param int $property_id
+	 *
+	 * @return $this
+	 */
+	public function setPropertyId($property_id)
+	{
+		$this->property_id = $property_id;
+
+		return $this;
+	}
+
+
+	/**
+	 * @return string
+	 */
+	public function getContractId()
+	{
+		return $this->contract_id;
+	}
+
+
+	/**
+	 * @param string $contract_id
+	 *
+	 * @return $this
+	 */
+	public function setContractId($contract_id)
+	{
+		$this->contract_id = $contract_id;
+
+		return $this;
+	}
+
+
+	/**
+	 * @return string
+	 */
+	public function getFirstName()
+	{
+		return $this->first_name;
+	}
+
+
+	/**
+	 * @param string $first_name
+	 *
+	 * @return $this
+	 */
+	public function setFirstName($first_name)
+	{
+		$this->first_name = $first_name;
+
+		return $this;
+	}
+
+
+	/**
+	 * @return string
+	 */
+	public function getLastName()
+	{
+		return $this->last_name;
+	}
+
+
+	/**
+	 * @param string $last_name
+	 *
+	 * @return $this
+	 */
+	public function setLastName($last_name)
+	{
+		$this->last_name = $last_name;
+
+		return $this;
+	}
+
+
+	/**
+	 * @return string
+	 */
+	public function getEmail()
+	{
+		return $this->email;
+	}
+
+
+	/**
+	 * @param string $email
+	 *
+	 * @return $this
+	 */
+	public function setEmail($email)
+	{
+		$this->email = $email;
+
+		return $this;
+	}
+
+
+	/**
+	 * @return string
+	 */
+	public function getPhone()
+	{
+		return $this->phone;
+	}
+
+
+	/**
+	 * @param string $phone
+	 *
+	 * @return $this
+	 */
+	public function setPhone($phone)
+	{
+		$this->phone = $phone;
+
+		return $this;
+	}
+
+
+	/**
+	 * @return string
+	 */
+	public function getTenantType()
+	{
+		return $this->tenant_type;
+	}
+
+
+	/**
+	 * @param string $tenant_type
+	 *
+	 * @return $this
+	 */
+	public function setTenantType($tenant_type)
+	{
+		$this->tenant_type = $tenant_type;
+
+		return $this;
+	}
+
+
+	/**
+	 * @return string
+	 */
+	public function getEnquiryMethod()
+	{
+		return $this->enquiry_method;
+	}
+
+
+	/**
+	 * @param string $enquiry_method
+	 *
+	 * @return $this
+	 */
+	public function setEnquiryMethod($enquiry_method)
+	{
+		$this->enquiry_method = $enquiry_method;
+
+		return $this;
+	}
+
+
+	/**
+	 * @return string
+	 */
+	public function getEnquiryType()
+	{
+		return $this->enquiry_type;
+	}
+
+
+	/**
+	 * @param string $enquiry_type
+	 *
+	 * @return $this
+	 */
+	public function setEnquiryType($enquiry_type)
+	{
+		$this->enquiry_type = $enquiry_type;
+
+		return $this;
+	}
+
+
+	/**
+	 * @return string
+	 */
+	public function getMessage()
+	{
+		return $this->message;
+	}
+
+
+	/**
+	 * @param string $message
+	 *
+	 * @return $this
+	 */
+	public function setMessage($message)
+	{
+		$this->message = $message;
+
+		return $this;
+	}
+}
diff --git a/src/Models/EnquirySaved.php b/src/Models/EnquirySaved.php
new file mode 100644
index 0000000..ceafc01
--- /dev/null
+++ b/src/Models/EnquirySaved.php
@@ -0,0 +1,36 @@
+<?php
+namespace SturentsLib\Api\Models;
+
+/**
+ * ** This file was generated automatically, you might want to avoid editing it **
+ */
+class EnquirySaved extends SwaggerModel
+{
+	/**
+	 * Hashed id of the created enquiry
+	 * @var string
+	 */
+	protected $enquiry_id = '';
+
+
+	/**
+	 * @return string
+	 */
+	public function getEnquiryId()
+	{
+		return $this->enquiry_id;
+	}
+
+
+	/**
+	 * @param string $enquiry_id
+	 *
+	 * @return $this
+	 */
+	public function setEnquiryId($enquiry_id)
+	{
+		$this->enquiry_id = $enquiry_id;
+
+		return $this;
+	}
+}
diff --git a/src/Models/PropertyManager.php b/src/Models/PropertyManager.php
index d95512b..64bbbc0 100644
--- a/src/Models/PropertyManager.php
+++ b/src/Models/PropertyManager.php
@@ -34,6 +34,14 @@ class PropertyManager extends SwaggerModel
 	 */
 	protected $company = '';
 
+	/**
+	 * True if the landlord has given the channel permission to send
+	 * enquiries for their listings (e.g. via POST /enquiry)
+	 *
+	 * @var bool
+	 */
+	protected $can_send_enquiries = false;
+
 
 	/**
 	 * @return string
@@ -121,4 +129,26 @@ public function setCompany($company)
 
 		return $this;
 	}
+
+
+	/**
+	 * @return bool
+	 */
+	public function getCanSendEnquiries()
+	{
+		return $this->can_send_enquiries;
+	}
+
+
+	/**
+	 * @param bool $can_send_enquiries
+	 *
+	 * @return $this
+	 */
+	public function setCanSendEnquiries($can_send_enquiries)
+	{
+		$this->can_send_enquiries = $can_send_enquiries;
+
+		return $this;
+	}
 }
diff --git a/src/Requests/GetProperties.php b/src/Requests/GetProperties.php
index b6203e8..98db3c9 100644
--- a/src/Requests/GetProperties.php
+++ b/src/Requests/GetProperties.php
@@ -20,7 +20,15 @@ class GetProperties extends SwaggerRequest
 	 * @var null
 	 */
 	public $page;
-	protected static array $query_params = ['page'];
+
+	/**
+	 * Should be set to "3" (defaults to "1.3" if not set and the 1.3 version is deprecated)'
+	 *
+	 *
+	 * @var null
+	 */
+	public $version;
+	protected static array $query_params = ['page', 'version'];
 
 
 	public function setPage($page)
@@ -29,6 +37,12 @@ public function setPage($page)
 	}
 
 
+	public function setVersion($version)
+	{
+		$this->version = $version;
+	}
+
+
 	/**
 	 * @return \SturentsLib\Api\Models\ListProperties|\SturentsLib\Api\Models\Error|\SturentsLib\Api\Models\AuthError|\SturentsLib\Api\Models\GetError|\SturentsLib\Api\Models\RateLimitError|list<\SturentsLib\Api\Models\ListProperties>|list<\SturentsLib\Api\Models\Error>|list<\SturentsLib\Api\Models\AuthError>|list<\SturentsLib\Api\Models\GetError>|list<\SturentsLib\Api\Models\RateLimitError>
 	 */
diff --git a/src/Requests/GetSummary.php b/src/Requests/GetSummary.php
index e80d63d..13bec55 100644
--- a/src/Requests/GetSummary.php
+++ b/src/Requests/GetSummary.php
@@ -10,6 +10,22 @@ class GetSummary extends SwaggerRequest
 	public const METHOD = 'GET';
 	public const URI = '/api/summary';
 
+	/**
+	 * Should be set to "3" (defaults to "1.3" if not set and the 1.3 version is deprecated)'
+	 *
+	 *
+	 * @var null
+	 */
+	public $version;
+	protected static array $query_params = ['version'];
+
+
+	public function setVersion($version)
+	{
+		$this->version = $version;
+	}
+
+
 	/**
 	 * @return \SturentsLib\Api\Models\PropertyManager|\SturentsLib\Api\Models\Error|\SturentsLib\Api\Models\AuthError|\SturentsLib\Api\Models\GetError|list<\SturentsLib\Api\Models\PropertyManager>|list<\SturentsLib\Api\Models\Error>|list<\SturentsLib\Api\Models\AuthError>|list<\SturentsLib\Api\Models\GetError>
 	 */
diff --git a/src/Requests/PostEnquiry.php b/src/Requests/PostEnquiry.php
new file mode 100644
index 0000000..2abe431
--- /dev/null
+++ b/src/Requests/PostEnquiry.php
@@ -0,0 +1,52 @@
+<?php
+namespace SturentsLib\Api\Requests;
+use SturentsLib\Api\Models\SwaggerModel;
+
+/**
+ * Submit a tenant enquiry
+ */
+class PostEnquiry extends SwaggerRequest
+{
+	public const METHOD = 'POST';
+	public const URI = '/api/enquiry';
+
+	/**
+	 * Should be set to "3" (defaults to "1.3" if not set and the 1.3 version is deprecated)'
+	 *
+	 *
+	 * @var null
+	 */
+	public $version;
+	protected static array $query_params = ['version'];
+
+
+	/**
+	 * @param \SturentsLib\Api\Models\EnquiryCreation $enquiry
+	 */
+	public function setBody(\SturentsLib\Api\Models\EnquiryCreation $enquiry)
+	{
+		$this->body = json_encode($enquiry, JSON_THROW_ON_ERROR);
+	}
+
+
+	public function setVersion($version)
+	{
+		$this->version = $version;
+	}
+
+
+	/**
+	 * @return \SturentsLib\Api\Models\EnquirySaved|\SturentsLib\Api\Models\SendDataError|\SturentsLib\Api\Models\AuthError|\SturentsLib\Api\Models\Error|list<\SturentsLib\Api\Models\EnquirySaved>|list<\SturentsLib\Api\Models\SendDataError>|list<\SturentsLib\Api\Models\AuthError>|list<\SturentsLib\Api\Models\Error>
+	 */
+	public function sendWith(SwaggerClient $client)
+	{
+		return $client->make($this, [
+			'200' => \SturentsLib\Api\Models\EnquirySaved::class,
+			'400' => \SturentsLib\Api\Models\SendDataError::class,
+			'401' => \SturentsLib\Api\Models\AuthError::class,
+			'403' => \SturentsLib\Api\Models\AuthError::class,
+			'404' => \SturentsLib\Api\Models\Error::class,
+			'default' => \SturentsLib\Api\Models\Error::class
+		]);
+	}
+}
diff --git a/swagger/api-channel.yml b/swagger/api-channel.yml
index ce1c898..8a9f78d 100644
--- a/swagger/api-channel.yml
+++ b/swagger/api-channel.yml
@@ -65,7 +65,7 @@ paths:
         - in: query
           name: version
           type: string
-          required: true
+          required: false
           description: |
             Should be set to "3" (defaults to "1.3" if not set and the 1.3 version is deprecated)'
       tags:
@@ -111,7 +111,7 @@ paths:
         - in: query
           name: version
           type: string
-          required: true
+          required: false
           description: |
             Should be set to "3" (defaults to "1.3" if not set and the 1.3 version is deprecated)'
       tags:
@@ -182,6 +182,53 @@ paths:
           $ref: '#/definitions/GetError'
         default:
           $ref: '#/definitions/Error'
+  /enquiry:
+    post:
+      summary: Submit a tenant enquiry
+      description: |
+        Channel-facing endpoint for submitting a tenant enquiry against a specific
+        property/contract term. Auth follows the same channel HMAC pattern as
+        other v3 API endpoints (timestamp + SHA256 HMAC of body+timestamp using
+        the channel's public key).
+
+        The landlord must have explicitly enabled your channel to send them
+        enquiries before this endpoint will accept requests for their properties.
+        Check the "can_send_enquiries" field returned by GET /summary for each
+        property manager to see whether this has been enabled - if it is false,
+        requests to this endpoint for that landlord will be rejected with a 403.
+      security:
+        - Channel: []
+          PropertyManager: []
+          Timestamp: []
+          Auth: []
+      parameters:
+        - in: query
+          name: version
+          type: string
+          required: false
+          description: |
+            Should be set to "3" (defaults to "1.3" if not set and the 1.3 version is deprecated)'
+        - in: body
+          name: Enquiry
+          schema:
+            $ref: '#/definitions/EnquiryCreation'
+      tags:
+        - Property listings
+      responses:
+        '200':
+          description: Indicates the created enquiry ID
+          schema:
+            $ref: '#/definitions/EnquirySaved'
+        '400':
+          $ref: '#/definitions/SendDataError'
+        '401':
+          $ref: '#/definitions/AuthError'
+        '403':
+          $ref: '#/definitions/AuthError'
+        '404':
+          $ref: '#/definitions/Error'
+        default:
+          $ref: '#/definitions/Error'
 definitions:
   GetError:
     description: |
@@ -200,6 +247,17 @@ definitions:
       error:
         type: string
         description: Message indicating the rate limit has been exceeded and when to try again
+  SendDataError:
+    description: |
+      There were problems with the input data in the request body.
+      These will be described in the "messages" field of the response
+    type: object
+    properties:
+      messages:
+        type: array
+        description: Keyed by field name (collapsed using . characters)
+        items:
+          type: string
   AuthError:
     description: |
       The key supplied did not match the property manager or channel
@@ -791,6 +849,11 @@ definitions:
         type: string
         description: |
           ID for the organisation this account belongs to on the StuRents website
+      can_send_enquiries:
+        type: boolean
+        description: |
+          True if the landlord has given the channel permission to send
+          enquiries for their listings (e.g. via POST /enquiry)
   Error:
     type: object
     properties:
@@ -984,3 +1047,51 @@ definitions:
         type: string
         description: |
           Date and time that the room summary was last updated
+  EnquiryCreation:
+    type: object
+    required:
+      - property_id
+      - contract_id
+      - first_name
+      - last_name
+      - email
+      - phone
+      - tenant_type
+      - enquiry_method
+      - enquiry_type
+    properties:
+      property_id:
+        type: integer
+        description: Plain (non-hashed) house id
+      contract_id:
+        type: string
+        description: Hashed availability id
+      first_name:
+        type: string
+      last_name:
+        type: string
+      email:
+        type: string
+        format: email
+      phone:
+        type: string
+      tenant_type:
+        type: string
+        enum: [student, professional, guardian]
+      enquiry_method:
+        type: string
+        enum: [phone, message]
+      enquiry_type:
+        type: string
+        enum: [enquire, book, viewing]
+      message:
+        type: string
+        description: |
+          Optional free-text message; used as the enquiry subject if provided,
+          otherwise a label derived from enquiry_type is used
+  EnquirySaved:
+    type: object
+    properties:
+      enquiry_id:
+        type: string
+        description: Hashed id of the created enquiry
diff --git a/swagger/api-display.yml b/swagger/api-display.yml
index 80f7626..33cf0bf 100644
--- a/swagger/api-display.yml
+++ b/swagger/api-display.yml
@@ -62,7 +62,7 @@ paths:
         - in: query
           name: version
           type: string
-          required: true
+          required: false
           description: |
             Should be set to "3" (defaults to "1.3" if not set and the 1.3 version is deprecated)'
       tags:
diff --git a/swagger/api-upload.yml b/swagger/api-upload.yml
index e8ffad5..f0a8eb3 100644
--- a/swagger/api-upload.yml
+++ b/swagger/api-upload.yml
@@ -84,7 +84,7 @@ paths:
         - in: query
           name: version
           type: string
-          required: true
+          required: false
           description: |
             Should be set to "3" (defaults to "1.3" if not set and the 1.3 version is deprecated)'
       tags:
diff --git a/swagger/api.yml b/swagger/api.yml
index 1075cba..e768146 100644
--- a/swagger/api.yml
+++ b/swagger/api.yml
@@ -98,7 +98,7 @@ paths:
         - in: query
           name: version
           type: string
-          required: true
+          required: false
           description: |
             Should be set to "3" (defaults to "1.3" if not set and the 1.3 version is deprecated)'
       tags:
@@ -135,7 +135,7 @@ paths:
         - in: query
           name: version
           type: string
-          required: true
+          required: false
           description: |
             Should be set to "3" (defaults to "1.3" if not set and the 1.3 version is deprecated)'
       responses:
@@ -697,6 +697,54 @@ paths:
           $ref: '#/definitions/GetError'
         default:
           $ref: '#/definitions/Error'
+  /enquiry:
+    post:
+      summary: Submit a tenant enquiry
+      description: |
+        Channel-facing endpoint for submitting a tenant enquiry against a specific
+        property/contract term. Auth follows the same channel HMAC pattern as
+        other v3 API endpoints (timestamp + SHA256 HMAC of body+timestamp using
+        the channel's public key).
+
+        The landlord must have explicitly enabled your channel to send them
+        enquiries before this endpoint will accept requests for their properties.
+        Check the "can_send_enquiries" field returned by GET /summary for each
+        property manager to see whether this has been enabled - if it is false,
+        requests to this endpoint for that landlord will be rejected with a 403.
+      security:
+        - Channel: []
+          PropertyManager: []
+          Timestamp: []
+          Auth: []
+      parameters:
+        - in: query
+          name: version
+          type: string
+          required: false
+          description: |
+            Should be set to "3" (defaults to "1.3" if not set and the 1.3 version is deprecated)'
+        - in: body
+          name: Enquiry
+          schema:
+            $ref: '#/definitions/EnquiryCreation'
+      tags:
+        - Changing data on StuRents
+        - Enquiries
+      responses:
+        '200':
+          description: Indicates the created enquiry ID
+          schema:
+            $ref: '#/definitions/EnquirySaved'
+        '400':
+          $ref: '#/definitions/SendDataError'
+        '401':
+          $ref: '#/definitions/AuthError'
+        '403':
+          $ref: '#/definitions/AuthError'
+        '404':
+          $ref: '#/definitions/Error'
+        default:
+          $ref: '#/definitions/Error'
 definitions:
   GetError:
     description: |
@@ -1518,6 +1566,11 @@ definitions:
         type: string
         description: |
           ID for the organisation this account belongs to on the StuRents website
+      can_send_enquiries:
+        type: boolean
+        description: |
+          True if the landlord has given the channel permission to send
+          enquiries for their listings (e.g. via POST /enquiry)
   BankAccount:
     properties:
       descriptor:
@@ -1550,6 +1603,54 @@ definitions:
       media_id:
         type: string
         description: Unique reference to the Media item on StuRents
+  EnquiryCreation:
+    type: object
+    required:
+      - property_id
+      - contract_id
+      - first_name
+      - last_name
+      - email
+      - phone
+      - tenant_type
+      - enquiry_method
+      - enquiry_type
+    properties:
+      property_id:
+        type: integer
+        description: Plain (non-hashed) house id
+      contract_id:
+        type: string
+        description: Hashed availability id
+      first_name:
+        type: string
+      last_name:
+        type: string
+      email:
+        type: string
+        format: email
+      phone:
+        type: string
+      tenant_type:
+        type: string
+        enum: [student, professional, guardian]
+      enquiry_method:
+        type: string
+        enum: [phone, message]
+      enquiry_type:
+        type: string
+        enum: [enquire, book, viewing]
+      message:
+        type: string
+        description: |
+          Optional free-text message; used as the enquiry subject if provided,
+          otherwise a label derived from enquiry_type is used
+  EnquirySaved:
+    type: object
+    properties:
+      enquiry_id:
+        type: string
+        description: Hashed id of the created enquiry
   Error:
     type: object
     properties: