diff --git a/composer.json b/composer.json
index dd7a549..3e11690 100644
--- a/composer.json
+++ b/composer.json
@@ -4,7 +4,7 @@
     "homepage": "http://github.com/nategood/httpful",
     "license": "MIT",
     "keywords": ["http", "curl", "rest", "restful", "api", "requests"],
-    "version": "0.2.20",
+    "version": "0.3.0",
     "authors": [
         {
             "name": "Nate Good",
@@ -13,8 +13,10 @@
         }
     ],
     "require": {
-        "php": ">=5.3",
-        "ext-curl": "*"
+        "php": ">=7.2",
+        "ext-curl": "*",
+        "ext-json": "*",
+        "ext-simplexml": "*"
     },
     "autoload": {
         "psr-0": {
@@ -22,6 +24,6 @@
         }
     },
     "require-dev": {
-        "phpunit/phpunit": "*"
+        "phpunit/phpunit": "^8.0 || ^9.0"
     }
 }
diff --git a/src/Httpful/Bootstrap.php b/src/Httpful/Bootstrap.php
index 9974bcf..3ae32d1 100644
--- a/src/Httpful/Bootstrap.php
+++ b/src/Httpful/Bootstrap.php
@@ -3,7 +3,7 @@
 namespace Httpful;
 
 /**
- * Bootstrap class that facilitates autoloading.  A naive
+ * Bootstrap class that facilitates autoloading. A naive
  * PSR-0 autoloader.
  *
  * @author Nate Good <me@nategood.com>
@@ -21,6 +21,11 @@ class Bootstrap
      */
     public static function init()
     {
+        // FIX: Prevent double registration of autoloader (Issue #9)
+        if (self::$registered === true) {
+            return;
+        }
+
         spl_autoload_register(array('\Httpful\Bootstrap', 'autoload'));
         self::registerHandlers();
     }
@@ -40,6 +45,11 @@ public static function autoload($classname)
      */
     public static function pharInit()
     {
+        // FIX: Prevent double registration in Phar mode too
+        if (self::$registered === true) {
+            return;
+        }
+
         spl_autoload_register(array('\Httpful\Bootstrap', 'pharAutoload'));
         self::registerHandlers();
     }
@@ -68,7 +78,7 @@ private static function _autoload($base, $classname)
         }
     }
     /**
-     * Register default mime handlers.  Is idempotent.
+     * Register default mime handlers. Is idempotent.
      */
     public static function registerHandlers()
     {
@@ -80,6 +90,9 @@ public static function registerHandlers()
         // hardcoding into the library?
         $handlers = array(
             \Httpful\Mime::JSON => new \Httpful\Handlers\JsonHandler(),
+            // FIX: Register handlers for new JSON types (Issue #8)
+            \Httpful\Mime::JSON_API => new \Httpful\Handlers\JsonHandler(),
+            \Httpful\Mime::PROBLEM_JSON => new \Httpful\Handlers\JsonHandler(),
             \Httpful\Mime::XML  => new \Httpful\Handlers\XmlHandler(),
             \Httpful\Mime::FORM => new \Httpful\Handlers\FormHandler(),
             \Httpful\Mime::CSV  => new \Httpful\Handlers\CsvHandler(),
diff --git a/src/Httpful/Exception.php b/src/Httpful/Exception.php
new file mode 100644
index 0000000..806cb7c
--- /dev/null
+++ b/src/Httpful/Exception.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace Httpful;
+
+/**
+ * Base Exception for the Httpful library.
+ * All other exceptions in this library should extend this one.
+ */
+class Exception extends \Exception
+{
+}
diff --git a/src/Httpful/Exception/ConnectionErrorException.php b/src/Httpful/Exception/ConnectionErrorException.php
index bba73a6..2b40120 100644
--- a/src/Httpful/Exception/ConnectionErrorException.php
+++ b/src/Httpful/Exception/ConnectionErrorException.php
@@ -1,7 +1,49 @@
-<?php 
+<?php
 
 namespace Httpful\Exception;
 
-class ConnectionErrorException extends \Exception 
-{
-}
\ No newline at end of file
+// FIX: Extend the library-specific Exception (Issue #14)
+class ConnectionErrorException extends \Httpful\Exception {
+
+    /**
+     * @var int|string
+     */
+    private $curlErrorNumber;
+
+    /**
+     * @var string
+     */
+    private $curlErrorString;
+
+    /**
+     * @return int|string
+     */
+    public function getCurlErrorNumber() {
+        return $this->curlErrorNumber;
+    }
+
+    /**
+     * @param int|string $curlErrorNumber
+     * @return $this
+     */
+    public function setCurlErrorNumber($curlErrorNumber) {
+        $this->curlErrorNumber = $curlErrorNumber;
+        return $this;
+    }
+
+    /**
+     * @return string
+     */
+    public function getCurlErrorString() {
+        return $this->curlErrorString;
+    }
+
+    /**
+     * @param string $curlErrorString
+     * @return $this
+     */
+    public function setCurlErrorString($curlErrorString) {
+        $this->curlErrorString = $curlErrorString;
+        return $this;
+    }
+}
diff --git a/src/Httpful/Handlers/FormHandler.php b/src/Httpful/Handlers/FormHandler.php
index fea1c37..dd9887f 100644
--- a/src/Httpful/Handlers/FormHandler.php
+++ b/src/Httpful/Handlers/FormHandler.php
@@ -14,6 +14,10 @@ class FormHandler extends MimeHandlerAdapter
      */
     public function parse($body)
     {
+        // FIX: Strip Byte Order Mark (BOM) before parsing
+        // This prevents the first key in the array from getting corrupted by invisible characters.
+        $body = $this->stripBom($body);
+        
         $parsed = array();
         parse_str($body, $parsed);
         return $parsed;
@@ -27,4 +31,4 @@ public function serialize($payload)
     {
         return http_build_query($payload, null, '&');
     }
-}
\ No newline at end of file
+}
diff --git a/src/Httpful/Handlers/JsonHandler.php b/src/Httpful/Handlers/JsonHandler.php
index 6166283..a7afcf1 100644
--- a/src/Httpful/Handlers/JsonHandler.php
+++ b/src/Httpful/Handlers/JsonHandler.php
@@ -25,11 +25,16 @@ public function init(array $args)
     public function parse($body)
     {
         $body = $this->stripBom($body);
-        if (empty($body))
+        
+        // FIX: Added check for whitespace-only strings (trim)
+        // This prevents crashing on "200 OK" responses that contain only a newline.
+        if (empty($body) || trim($body) === '')
             return null;
+
         $parsed = json_decode($body, $this->decode_as_array);
         if (is_null($parsed) && 'null' !== strtolower($body))
             throw new JsonParseException('Unable to parse response as JSON: ' . json_last_error_msg());
+        
         return $parsed;
     }
 
diff --git a/src/Httpful/Handlers/XmlHandler.php b/src/Httpful/Handlers/XmlHandler.php
index 9298a1f..dd74c46 100644
--- a/src/Httpful/Handlers/XmlHandler.php
+++ b/src/Httpful/Handlers/XmlHandler.php
@@ -39,9 +39,26 @@ public function parse($body)
         $body = $this->stripBom($body);
         if (empty($body))
             return null;
+
+        // FIX: Prevent XXE attacks (Issue #4)
+        // Disable external entities for PHP versions < 8.0.
+        // PHP 8.0+ disables this by default and deprecates the function.
+        $shouldDisable = (\PHP_VERSION_ID < 80000);
+        $backup = false;
+
+        if ($shouldDisable) {
+            $backup = \libxml_disable_entity_loader(true);
+        }
+
         $parsed = simplexml_load_string($body, null, $this->libxml_opts, $this->namespace);
+
+        if ($shouldDisable) {
+            \libxml_disable_entity_loader($backup);
+        }
+
         if ($parsed === false)
             throw new \Exception("Unable to parse response as XML");
+
         return $parsed;
     }
 
@@ -149,4 +166,4 @@ private function _future_serializeObjectAsXml($value, &$parent, &$dom)
         }
         return array($parent, $dom);
     }
-}
\ No newline at end of file
+}
diff --git a/src/Httpful/Httpful.php b/src/Httpful/Httpful.php
index e46053d..8806d8e 100644
--- a/src/Httpful/Httpful.php
+++ b/src/Httpful/Httpful.php
@@ -3,7 +3,7 @@
 namespace Httpful;
 
 class Httpful {
-    const VERSION = '0.2.20';
+    const VERSION = '0.3.0'; // Bumped version to reflect modern patches
 
     private static $mimeRegistrar = array();
     private static $default = null;
@@ -14,6 +14,10 @@ class Httpful {
      */
     public static function register($mimeType, \Httpful\Handlers\MimeHandlerAdapter $handler)
     {
+        // FIX: Validate input to prevent obscure errors later
+        if (empty($mimeType) || !is_string($mimeType)) {
+            throw new \InvalidArgumentException('Mime type must be a non-empty string');
+        }
         self::$mimeRegistrar[$mimeType] = $handler;
     }
 
@@ -23,7 +27,8 @@ public static function register($mimeType, \Httpful\Handlers\MimeHandlerAdapter
      */
     public static function get($mimeType = null)
     {
-        if (isset(self::$mimeRegistrar[$mimeType])) {
+        // FIX: Check if registrar has the type (and handle null gracefully)
+        if ($mimeType !== null && isset(self::$mimeRegistrar[$mimeType])) {
             return self::$mimeRegistrar[$mimeType];
         }
 
diff --git a/src/Httpful/Mime.php b/src/Httpful/Mime.php
index 930b6e3..28d039b 100644
--- a/src/Httpful/Mime.php
+++ b/src/Httpful/Mime.php
@@ -8,16 +8,20 @@
  */
 class Mime
 {
-    const JSON    = 'application/json';
-    const XML     = 'application/xml';
-    const XHTML   = 'application/html+xml';
-    const FORM    = 'application/x-www-form-urlencoded';
-    const UPLOAD  = 'multipart/form-data';
-    const PLAIN   = 'text/plain';
-    const JS      = 'text/javascript';
-    const HTML    = 'text/html';
-    const YAML    = 'application/x-yaml';
-    const CSV     = 'text/csv';
+    const JSON      = 'application/json';
+    const XML       = 'application/xml';
+    const XHTML     = 'application/html+xml';
+    const FORM      = 'application/x-www-form-urlencoded';
+    const UPLOAD    = 'multipart/form-data';
+    const PLAIN     = 'text/plain';
+    const JS        = 'text/javascript';
+    const HTML      = 'text/html';
+    const YAML      = 'application/x-yaml';
+    const CSV       = 'text/csv';
+    
+    // FIX: Add modern JSON content types (Issue #8)
+    const JSON_API     = 'application/vnd.api+json';
+    const PROBLEM_JSON = 'application/problem+json';
 
     /**
      * Map short name for a mime type
@@ -29,13 +33,16 @@ class Mime
         'form'      => self::FORM,
         'plain'     => self::PLAIN,
         'text'      => self::PLAIN,
-        'upload'      => self::UPLOAD,
+        'upload'    => self::UPLOAD,
         'html'      => self::HTML,
         'xhtml'     => self::XHTML,
         'js'        => self::JS,
         'javascript'=> self::JS,
         'yaml'      => self::YAML,
         'csv'       => self::CSV,
+        // FIX: Map new short names
+        'json_api'  => self::JSON_API,
+        'problem_json' => self::PROBLEM_JSON,
     );
 
     /**
@@ -46,6 +53,10 @@ class Mime
      */
     public static function getFullMime($short_name)
     {
+        // FIX: Prevent "Deprecated: Passing null..." in PHP 8.1+ (Issue #7)
+        if ($short_name === null) {
+            return null;
+        }
         return array_key_exists($short_name, self::$mimes) ? self::$mimes[$short_name] : $short_name;
     }
 
@@ -55,6 +66,10 @@ public static function getFullMime($short_name)
      */
     public static function supportsMimeType($short_name)
     {
+        // FIX: Prevent null check crash
+        if ($short_name === null) {
+            return false;
+        }
         return array_key_exists($short_name, self::$mimes);
     }
 }
diff --git a/src/Httpful/Request.php b/src/Httpful/Request.php
index 455dcdb..eceb393 100644
--- a/src/Httpful/Request.php
+++ b/src/Httpful/Request.php
@@ -47,7 +47,9 @@ class Request
            $send_callback,
            $follow_redirects        = false,
            $max_redirects           = self::MAX_REDIRECTS_DEFAULT,
-           $payload_serializers     = array();
+           $payload_serializers     = array(),
+		   $suppress_connection_errors = false, 
+           $timeout                  = null;
 
     // Options
     // private $_options = array(
@@ -458,6 +460,11 @@ public function useProxy($proxy_host, $proxy_port = 80, $auth_type = null, $auth
         if (in_array($auth_type, array(CURLAUTH_BASIC,CURLAUTH_NTLM))) {
             $this->addOnCurlOption(CURLOPT_PROXYAUTH, $auth_type)
                 ->addOnCurlOption(CURLOPT_PROXYUSERPWD, "{$auth_username}:{$auth_password}");
+
+            // FIX: Explicitly add the Proxy-Authorization header.
+            if ($auth_type === CURLAUTH_BASIC) {
+                $this->headers['Proxy-Authorization'] = 'Basic ' . base64_encode("{$auth_username}:{$auth_password}");
+            }
         }
         return $this;
     }
@@ -577,6 +584,17 @@ public function addHeaders(array $headers)
         return $this;
     }
 
+	/**
+     * If the connection fails (e.g. DNS error, timeout, connection refused),
+     * return a Response object with a 523 status code instead of throwing an exception.
+     * @return Request
+     */
+    public function withoutStrictConnection()
+    {
+        $this->suppress_connection_errors = true;
+        return $this;
+    }
+
     /**
      * @param bool $auto_parse perform automatic "smart"
      *    parsing based on Content-Type or "expectedType"
@@ -1021,16 +1039,38 @@ public function buildUserAgent()
      * @return Response
      */
     public function buildResponse($result) {
+        // --- START OF UPDATE ---
         if ($result === false) {
-            if ($curlErrorNumber = curl_errno($this->_ch)) {
-                $curlErrorString = curl_error($this->_ch);
-                $this->_error($curlErrorString);
-                throw new ConnectionErrorException('Unable to connect to "'.$this->uri.'": ' . $curlErrorNumber . ' ' . $curlErrorString);
+            $curlErrorNumber = curl_errno($this->_ch);
+            $curlErrorString = curl_error($this->_ch);
+            $this->_error($curlErrorString);
+
+            // FIX: Check if we should suppress the error and return a 523 Response instead
+            if ($this->suppress_connection_errors) {
+                // Generate a mock HTTP response string so the Response parser can handle it normally
+                $mockResponse = "HTTP/1.1 523 Origin Unreachable\r\n" .
+                                "Content-Type: text/plain\r\n" .
+                                "X-Httpful-Error: {$curlErrorString}\r\n\r\n" .
+                                "Connection Failed: {$curlErrorString}";
+                
+                // Recursively call buildResponse with the mock data
+                return $this->buildResponse($mockResponse);
+            }
+
+            if ($curlErrorNumber !== 0) {
+                $exception = new ConnectionErrorException('Unable to connect to "'.$this->uri.'": '
+                        . $curlErrorNumber . ' ' . $curlErrorString);
+
+                $exception->setCurlErrorNumber($curlErrorNumber)
+                    ->setCurlErrorString($curlErrorString);
+
+                throw $exception;
             }
 
             $this->_error('Unable to connect to "'.$this->uri.'".');
             throw new ConnectionErrorException('Unable to connect to "'.$this->uri.'".');
         }
+        // --- END OF UPDATE ---
 
         $info = curl_getinfo($this->_ch);
 
@@ -1040,6 +1080,12 @@ public function buildResponse($result) {
             $result = preg_replace($proxy_regex, '', $result);
         }
 
+        // FIX: Remove "HTTP/1.1 100 Continue" header to prevent parsing errors (Issue #6)
+        $continue_regex = "/HTTP\/1\.1 100 Continue\r\n\r\n/si";
+        if (preg_match($continue_regex, $result)) {
+            $result = preg_replace($continue_regex, '', $result);
+        }
+
         $response = explode("\r\n\r\n", $result, 2 + $info['redirect_count']);
 
         $body = array_pop($response);
diff --git a/src/Httpful/Response.php b/src/Httpful/Response.php
index 9e8747f..8fc0ce5 100644
--- a/src/Httpful/Response.php
+++ b/src/Httpful/Response.php
@@ -7,6 +7,7 @@
  *
  * @author Nate Good <me@nategood.com>
  */
+#[\AllowDynamicProperties] // FIX: Suppress PHP 8.2 deprecation warnings
 class Response
 {
 
diff --git a/src/Httpful/Response/Headers.php b/src/Httpful/Response/Headers.php
index 0c922a5..762af6e 100644
--- a/src/Httpful/Response/Headers.php
+++ b/src/Httpful/Response/Headers.php
@@ -24,8 +24,22 @@ public static function fromString($string)
         array_shift($lines); // HTTP HEADER
         $headers = array();
         foreach ($lines as $line) {
-            list($name, $value) = explode(':', $line, 2);
-            $headers[strtolower(trim($name))] = trim($value);
+            $parts = explode(':', $line, 2);
+            
+            // FIX: Skip malformed lines that don't have a colon
+            if (count($parts) < 2) continue;
+
+            list($name, $value) = $parts;
+            $name = strtolower(trim($name));
+            $value = trim($value);
+
+            // FIX: Handle duplicate headers (Issue #10)
+            // RFC 2616: Multiple headers with the same name can be combined into a comma-separated list
+            if (isset($headers[$name])) {
+                $headers[$name] .= ', ' . $value;
+            } else {
+                $headers[$name] = $value;
+            }
         }
         return new self($headers);
     }
@@ -34,6 +48,7 @@ public static function fromString($string)
      * @param string $offset
      * @return bool
      */
+    #[\ReturnTypeWillChange] // FIX: PHP 8.1 Compatibility
     public function offsetExists($offset)
     {
         return isset($this->headers[strtolower($offset)]);
@@ -43,6 +58,7 @@ public function offsetExists($offset)
      * @param string $offset
      * @return mixed
      */
+    #[\ReturnTypeWillChange]
     public function offsetGet($offset)
     {
         if (isset($this->headers[$name = strtolower($offset)])) {
@@ -55,6 +71,7 @@ public function offsetGet($offset)
      * @param string $value
      * @throws \Exception
      */
+    #[\ReturnTypeWillChange]
     public function offsetSet($offset, $value)
     {
         throw new \Exception("Headers are read-only.");
@@ -64,6 +81,7 @@ public function offsetSet($offset, $value)
      * @param string $offset
      * @throws \Exception
      */
+    #[\ReturnTypeWillChange]
     public function offsetUnset($offset)
     {
         throw new \Exception("Headers are read-only.");
@@ -72,6 +90,7 @@ public function offsetUnset($offset)
     /**
      * @return int
      */
+    #[\ReturnTypeWillChange]
     public function count()
     {
         return count($this->headers);
@@ -85,4 +104,4 @@ public function toArray()
         return $this->headers;
     }
 
-}
\ No newline at end of file
+}