diff --git a/VERSION b/VERSION
new file mode 100644
index 00000000..27645834
--- /dev/null
+++ b/VERSION
@@ -0,0 +1 @@
+2.0.13-dev
diff --git a/composer.json b/composer.json
index 623ad5c2..6e268f92 100644
--- a/composer.json
+++ b/composer.json
@@ -48,6 +48,9 @@
             "@cs",
             "@stan"
         ],
+        "release": [
+            "release VERSION"
+        ],
         "coveralls": "php ./vendor/bin/php-coveralls -v"
     }
 }
diff --git a/src/Connector/Client.php b/src/Connector/Client.php
index 25860e60..bf795d4f 100644
--- a/src/Connector/Client.php
+++ b/src/Connector/Client.php
@@ -40,7 +40,7 @@ public function __construct(ConnectorInterface $connector)
     }
 
     /**
-     * Client factory method for instantiating .
+     * Client factory method for instantiating.
      *
      * @param ConnectorInterface $connector
      *
@@ -56,20 +56,64 @@ public static function factory(ConnectorInterface $connector)
     }
 
     /**
-     * @inheritdoc
+     * Returns the current version of the library.
+     *
+     * @return string
+     * @throws \Exception
      */
-    public function request(string $verb, string $path, array $options = [])
+    public function getVersion()
     {
-        // @TODO follow this up by removing $options from the parameters able
-        // to be passed into this function and instead solely relying on the
-        // addOption() method as this can then be tested.
+        if ($file = @file_get_contents(dirname(dirname(__DIR__)) . '/VERSION')) {
+            return trim($file);
+        } else {
+            throw new \Exception('No VERSION file');
+        }
+    }
+
+    /**
+     * Allows the library to modify the request prior to making the call to the API.
+     */
+    public function modifyOptions($options = []): array
+    {
+        // Add the user agent header here so it can't be removed by other libraries.
+        $this->addOption('headers', [
+            'User-Agent' => sprintf(
+                "%s/%s (https://github.com/typhonius/acquia-php-sdk-v2)",
+                'acquia-php-sdk-v2',
+                $this->getVersion()
+            )
+        ]);
+
+        // Combine options set globally e.g. headers with options set by individual API calls e.g. form_params.
         $options = $this->options + $options;
-        $options['query'] = $this->query;
 
+        // This library can be standalone or as a dependency. Dependent libraries may also set their own user agent
+        // which will make $options['headers']['User-Agent'] an array.
+        // We need to reverse the array of User-Agent headers to order this library's header first in log files.
+        // As Guzzle joins arrays with a comma, we must implode with a space here to pass Guzzle a string.
+        if (is_array($options['headers']['User-Agent'])) {
+            $options['headers']['User-Agent'] = implode(' ', array_reverse($options['headers']['User-Agent']));
+        }
+
+        $options['query'] = $this->query;
         if (!empty($options['query']['filter']) && is_array($options['query']['filter'])) {
             // Default to an AND filter.
             $options['query']['filter'] = implode(',', $options['query']['filter']);
         }
+
+        return $options;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function request(string $verb, string $path, array $options = [])
+    {
+        // @TODO follow this up by removing $options from the parameters able
+        // to be passed into this function and instead solely relying on the
+        // addOption() method as this can then be tested.
+        $options = $this->modifyOptions($options);
+
         $response = $this->makeRequest($verb, $path, $options);
 
         return $this->processResponse($response);
@@ -78,7 +122,7 @@ public function request(string $verb, string $path, array $options = [])
     /**
      * @inheritdoc
      */
-    public function makeRequest(string $verb, string $path, array $options = [])
+    public function makeRequest(string $verb, string $path, array $options = []): ResponseInterface
     {
         try {
             $response = $this->connector->sendRequest($verb, $path, $options);
@@ -116,7 +160,7 @@ public function processResponse(ResponseInterface $response)
     /**
      * @inheritdoc
      */
-    public function getQuery()
+    public function getQuery(): array
     {
         return $this->query;
     }
@@ -124,7 +168,7 @@ public function getQuery()
     /**
      * @inheritdoc
      */
-    public function clearQuery()
+    public function clearQuery(): void
     {
         $this->query = [];
     }
@@ -132,7 +176,7 @@ public function clearQuery()
     /**
      * @inheritdoc
      */
-    public function addQuery($name, $value)
+    public function addQuery($name, $value): void
     {
         $this->query = array_merge_recursive($this->query, [$name => $value]);
     }
@@ -140,7 +184,7 @@ public function addQuery($name, $value)
     /**
      * @inheritdoc
      */
-    public function getOptions()
+    public function getOptions(): array
     {
         return $this->options;
     }
@@ -148,7 +192,7 @@ public function getOptions()
     /**
      * @inheritdoc
      */
-    public function clearOptions()
+    public function clearOptions(): void
     {
         $this->options = [];
     }
@@ -156,7 +200,7 @@ public function clearOptions()
     /**
      * @inheritdoc
      */
-    public function addOption($name, $value)
+    public function addOption($name, $value): void
     {
         $this->options = array_merge_recursive($this->options, [$name => $value]);
     }
diff --git a/tests/Endpoints/ClientTest.php b/tests/Endpoints/ClientTest.php
index 062a2a4d..15148d20 100644
--- a/tests/Endpoints/ClientTest.php
+++ b/tests/Endpoints/ClientTest.php
@@ -75,4 +75,70 @@ public function testOptions()
         $client->clearOptions();
         $this->assertTrue(empty($client->getOptions()));
     }
+
+    public function testModifyOptions()
+    {
+        $client = $this->getMockClient();
+
+        // Set a number of options and queries as a dependent library would.
+        $client->addOption('headers', ['User-Agent' => 'AcquiaCli/4.20']);
+        $client->addQuery('filter', 'name=@*2014*');
+        $client->addQuery('filter', 'type=@*true*');
+        $client->addQuery('limit', '1');
+
+        // Set options as an endpoint call would.
+        $options = [
+            'form_params' => [
+                'source' => 'source',
+                'message' => 'message',
+            ],
+        ];
+
+        // Modify the request to ensure that all of the above get merged correctly.
+        $actualOptions = $client->modifyOptions($options);
+
+        $version = $client->getVersion();
+        $expectedOptions = [
+            'headers' => [
+                'User-Agent' => sprintf('acquia-php-sdk-v2/%s (https://github.com/typhonius/acquia-php-sdk-v2) AcquiaCli/4.20', $version)
+            ],
+            'form_params' => [
+                'source' => 'source',
+                'message' => 'message'
+            ],
+            'query' => [
+                'filter' => 'name=@*2014*,type=@*true*',
+                'limit' => '1'
+            ]
+        ];
+
+        $this->assertEquals($expectedOptions, $actualOptions);
+    }
+
+    public function testVersion()
+    {
+        $versionFile = sprintf('%s/VERSION', dirname(dirname(__DIR__)));
+        $version = trim(file_get_contents($versionFile));
+
+        $client = $this->getMockClient();
+        $actualValue = $client->getVersion();
+
+        $this->assertEquals($version, $actualValue);
+    }
+
+    public function testMissingVersion()
+    {
+        $versionFile = sprintf('%s/VERSION', dirname(dirname(__DIR__)));
+        $versionFileBak = sprintf('%s.bak', $versionFile);
+        rename($versionFile, $versionFileBak);
+
+        try {
+            $client = $this->getMockClient();
+            $version = $client->getVersion();
+        } catch (\Exception $e) {
+            $this->assertEquals('Exception', get_class($e));
+            $this->assertEquals('No VERSION file', $e->getMessage());
+        }
+        rename($versionFileBak, $versionFile);
+    }
 }