diff --git a/README.md b/README.md
index ee9b524..bc6b0ef 100644
--- a/README.md
+++ b/README.md
@@ -31,6 +31,12 @@ Register checks in your own `_config.php` - see the `_config.php` in this module
  * `HasClassCheck`: Check that the given class exists.
     This can be used to check that PHP modules or features are installed.
  * `FileWriteableCheck`: Check that the given file is writeable.
+ * `FileAgeCheck`: Checks for the maximum age of one or more files or folders.
+    Useful for files which should be frequently auto-generated, 
+    like static caches, as well as for backup files and folders.
+ * `ExternalURLCheck`: Checks that one or more URLs are reachable via HTTP.
+ * `SMTPConnectCheck`: Checks if the SMTP connection configured through PHP.ini works as expected.
+
 ## Adding more checks
 
 To add more checks, you should put additional `EnvironmentCheckSuite::register` calls into your `_config.php`.  See the `_config.php` file of this mode for examples.
diff --git a/code/checks/ExternalURLCheck.php b/code/checks/ExternalURLCheck.php
new file mode 100644
index 0000000..a8a09b5
--- /dev/null
+++ b/code/checks/ExternalURLCheck.php
@@ -0,0 +1,110 @@
+<?php
+/**
+ * Checks that one or more URLs are reachable via HTTP.
+ * Note that the HTTP connectivity can just be verified from the server to the remote URL,
+ * it can still fail if the URL in question is requested by the client, e.g. through an iframe.
+ * 
+ * Requires curl to present, so ensure to check it before with the following:
+ * <code>EnvironmentCheckSuite::register('check', 'HasFunctionCheck("curl_init")', "Does PHP have CURL support?");</code>
+ */
+class ExternalURLCheck implements EnvironmentCheck {
+
+	/**
+	 * @var array
+	 */
+	protected $urls = array();
+
+	/**
+	 * @var Int Timeout in seconds.
+	 */
+	protected $timeout;
+
+	/**
+	 * @param String Space separated list of absolute URLs 
+	 *  (can't be an array as we're using Object::create() with strings for the constructor signature)
+	 */
+	function __construct($urls, $timeout = 15) {
+		if($urls) $this->urls = explode(' ', $urls);
+		$this->timeout = $timeout;
+	}
+
+	function check() {
+		$urls = $this->getURLs();
+
+		$chs = array();
+		foreach($urls as $url)	{
+			$ch = curl_init();
+			$chs[] = $ch;
+			curl_setopt_array($ch, $this->getCurlOpts($url));
+		}	
+		// Parallel execution for faster performance
+		$mh = curl_multi_init();
+		foreach($chs as $ch) curl_multi_add_handle($mh,$ch);
+		
+		$active = null;
+		// Execute the handles
+		do {
+			$mrc = curl_multi_exec($mh, $active);
+		} while ($mrc == CURLM_CALL_MULTI_PERFORM);
+
+		while ($active && $mrc == CURLM_OK) {
+			if (curl_multi_select($mh) != -1) {
+				do {
+						$mrc = curl_multi_exec($mh, $active);
+				} while ($mrc == CURLM_CALL_MULTI_PERFORM);
+			}
+		}
+
+		$hasError = false;
+		$msgs = array();
+		foreach($chs as $ch) {
+			$url = curl_getinfo($ch, CURLINFO_EFFECTIVE_URL);
+			$code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
+			if(curl_errno($ch) || $code >= 400) {
+				$hasError = true;
+				$msgs[] = sprintf(
+					'Error retrieving "%s": %s (Code: %s)',
+					$url,
+					curl_error($ch),
+					$code
+				);
+			} else {
+				$msgs[] = sprintf(
+					'Success retrieving "%s" (Code: %s)',
+					$url,
+					$code
+				);
+			}
+		}
+
+		// Close the handles
+		foreach($chs as $ch) curl_multi_remove_handle($mh, $ch);
+		curl_multi_close($mh);
+		
+		if($hasError) {
+			return array(EnvironmentCheck::ERROR, implode(', ', $msgs));
+		} else {
+			return array(EnvironmentCheck::OK, implode(', ', $msgs));
+		}
+	}
+
+	/**
+	 * @return Array
+	 */
+	protected function getCurlOpts($url) {
+		return array(
+			CURLOPT_URL => $url,
+			CURLOPT_HEADER => 0,
+			CURLOPT_RETURNTRANSFER => 1,
+			CURLOPT_FAILONERROR => 1,
+			CURLOPT_TIMEOUT => $this->timeout,
+		);
+	}
+
+	/**
+	 * @return Array
+	 */
+	protected function getURLs() {
+		return $this->urls;
+	}
+}
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diff --git a/code/checks/FileAgeCheck.php b/code/checks/FileAgeCheck.php
new file mode 100644
index 0000000..b531983
--- /dev/null
+++ b/code/checks/FileAgeCheck.php
@@ -0,0 +1,106 @@
+<?php
+/**
+ * Checks for the maximum age of one or more files or folders.
+ * Useful for files which should be frequently auto-generated, 
+ * like static caches, as well as for backup files and folders.
+ * Does NOT check for existence of a file (will silently fail).
+ *
+ * Examples:
+ * // Checks that Requirements::combine_files() has regenerated files in the last 24h
+ * EnvironmentCheckSuite::register(
+ * 	'check', 
+ * 	'FileAgeCheck("' . ASSETS_PATH . '/_combined_files/*.js' . '", "-1 day", '>', " . FileAgeCheck::CHECK_ALL) . "'
+ * );
+ * 
+ * // Checks that at least one backup folder has been created in the last 24h
+ * EnvironmentCheckSuite::register(
+ * 	'check', 
+ * 	'FileAgeCheck("' . BASE_PATH . '/../backups/*' . '", "-1 day", '>', " . FileAgeCheck::CHECK_SINGLE) . "'
+ * );
+ */
+class FileAgeCheck implements EnvironmentCheck {
+
+	const CHECK_SINGLE = 1;
+
+	const CHECK_ALL = 2;
+	
+	/**
+	 * @var String Absolute path to a file or folder, compatible with glob().
+	 */
+	protected $path;
+
+	/**
+	 * @var String strtotime() compatible relative date specification.
+	 */
+	protected $relativeAge;
+
+	/**
+	 * @var String The function to use for checking file age,
+	 * so filemtime(), filectime() or fileatime().
+	 */
+	protected $checkFn;
+
+	/**
+	 * @var Int Constant, check for a single file to match age criteria, or all of them.
+	 */
+	protected $checkType;
+
+	/**
+	 * @var String Either '>' or '<'.
+	 */
+	protected $compareOperand;
+
+	function __construct($path, $relativeAge, $compareOperand = '>', $checkType = null, $checkFn = 'filemtime') {
+		$this->path = $path;
+		$this->relativeAge = $relativeAge;
+		$this->checkFn = $checkFn;
+		$this->checkType = ($checkType) ? $checkType : self::CHECK_SINGLE;
+		$this->compareOperand = $compareOperand;
+	}
+
+	function check() {
+		$cutoffTime =  strtotime($this->relativeAge, SS_Datetime::now()->Format('U'));
+		$files = $this->getFiles();
+		$invalidFiles = array();
+		$validFiles = array();
+		$checkFn = $this->checkFn;
+		$allValid = true;
+		if($files) foreach($files as $file) {
+			$fileTime = $checkFn($file);
+			$valid = ($this->compareOperand == '>') ? ($fileTime >= $cutoffTime) : ($fileTime <= $cutoffTime);
+			if($valid) {
+				$validFiles[] = $file;
+			} else {
+				$invalidFiles[] = $file;
+				if($this->checkType == self::CHECK_ALL) {
+					return array(
+						EnvironmentCheck::ERROR,
+						sprintf(
+							'File "%s" doesn\'t match age check (compare %s: %s, actual: %s)', 
+							$file, $this->compareOperand, date('c', $cutoffTime), date('c', $fileTime)
+						)
+					);	
+				}
+			}
+		}
+
+		// If at least one file was valid, count as passed
+		if($this->checkType == self::CHECK_SINGLE && count($invalidFiles) < count($files)) {
+			return array(EnvironmentCheck::OK, '');
+		} else {
+			return array(
+				EnvironmentCheck::ERROR,
+				sprintf('No files matched criteria (%s %s)', $this->compareOperand, date('c', $cutoffTime))
+			);
+		}
+			
+	}
+
+	/**
+	 * @return Array Of absolute file paths
+	 */
+	protected function getFiles() {
+		return glob($this->path);
+	}
+
+}
\ No newline at end of file
diff --git a/code/checks/SMTPConnectCheck.php b/code/checks/SMTPConnectCheck.php
new file mode 100644
index 0000000..d3dfb8c
--- /dev/null
+++ b/code/checks/SMTPConnectCheck.php
@@ -0,0 +1,58 @@
+<?php
+/**
+ * Checks if the SMTP connection configured through PHP.ini works as expected.
+ * Only checks socket connection with HELO command, not actually sending the email.
+ */
+class SMTPConnectCheck implements EnvironmentCheck {
+
+	/**
+	 * @var String
+	 */
+	protected $host;
+
+	/**
+	 * @var Int
+	 */
+	protected $port;
+
+	/**
+	 * @var Int In seconds
+	 */
+	protected $timeout;
+
+	/**
+	 * @param String
+	 * @param Int
+	 */
+	function __construct($host = null, $port = null, $timeout = 15) {
+		$this->host = ($host) ? $host : ini_get('SMTP');
+		if(!$this->host) $this->host = 'localhost';
+		
+		$this->port = ($port) ? $port : ini_get('smtp_port');
+		if(!$this->port) $this->port = 25;
+
+		$this->timeout = $timeout;
+	}
+
+	function check() {
+		$f = @fsockopen($this->host, $this->port, $errno, $errstr, $this->timeout);
+		if(!$f) {
+			return array(
+				EnvironmentCheck::ERROR, 
+				sprintf("Couldn't connect to SMTP on %s:%s (Error: %s %s)", $this->host, $this->port, $errno, $errstr)
+			);
+		}
+
+		fwrite($f, "HELO its_me\r\n");
+		$response = fread($f, 26);
+		if(substr($response, 0, 3) != '220') {
+			return array(
+				EnvironmentCheck::ERROR,
+				sprintf("Invalid mail server response: %s", $response)
+			);
+		}
+
+		return array(EnvironmentCheck::OK, '');
+
+	}
+}
\ No newline at end of file