diff --git a/common/framework/Timer.php b/common/framework/Timer.php
index a33b661f2..b27cf7ff1 100644
--- a/common/framework/Timer.php
+++ b/common/framework/Timer.php
@@ -20,11 +20,11 @@ class Timer
 	 * @param string $name (optional)
 	 * @return float
 	 */
-	public static function start($name = null)
+	public static function start(string $name = ''): float
 	{
 		$timestamp = microtime(true);
 
-		if ($name === null)
+		if ($name === '')
 		{
 			$name = 'anon-timer-' . $timestamp;
 		}
@@ -37,17 +37,17 @@ class Timer
 	 * Stop a timer and return the elapsed time.
 	 *
 	 * If the name is not given, the most recently started timer will be stopped.
-	 * If no timer has been started, this method returns false.
+	 * If no timer has been started, this method returns zero.
 	 *
 	 * @param string $name (optional)
-	 * @return float|false
+	 * @return float
 	 */
-	public static function stop($name = null)
+	public static function stop(string $name = ''): float
 	{
 		$timestamp = microtime(true);
 		$started_timestamp = 0;
 
-		if ($name === null)
+		if ($name === '')
 		{
 			if (count(self::$_timestamps))
 			{
@@ -55,7 +55,7 @@ class Timer
 			}
 			else
 			{
-				return false;
+				return 0;
 			}
 		}
 		elseif (array_key_exists($name, self::$_timestamps))
@@ -65,7 +65,7 @@ class Timer
 		}
 		else
 		{
-			return false;
+			return 0;
 		}
 
 		return $timestamp - $started_timestamp;
@@ -75,15 +75,15 @@ class Timer
 	 * Stop a timer and return the elapsed time in a human-readable format.
 	 *
 	 * If the name is not given, the most recently started timer will be stopped.
-	 * If no timer has been started, this method returns false.
+	 * If no timer has been started, this method returns '0'.
 	 *
 	 * @param string $name (optional)
-	 * @return string|false
+	 * @return string
 	 */
-	public static function stopFormat($name = null)
+	public static function stopFormat(string $name = ''): string
 	{
 		$result = self::stop($name);
-		if ($result === false) return $result;
+		if ($result === 0) return '0';
 		return number_format($result * 1000, 1, '.', ',') . 'ms';
 	}
 
@@ -92,7 +92,7 @@ class Timer
 	 *
 	 * @return float
 	 */
-	public static function sinceStartup()
+	public static function sinceStartup(): float
 	{
 		return microtime(true) - \RX_MICROTIME;
 	}
@@ -102,7 +102,7 @@ class Timer
 	 *
 	 * @return string
 	 */
-	public static function sinceStartupFormat()
+	public static function sinceStartupFormat(): string
 	{
 		return number_format((microtime(true) - \RX_MICROTIME) * 1000, 1, '.', ',') . 'ms';
 	}
diff --git a/common/framework/UA.php b/common/framework/UA.php
index 521b707db..a979de65b 100644
--- a/common/framework/UA.php
+++ b/common/framework/UA.php
@@ -32,7 +32,7 @@ class UA
 	 * @param string $ua (optional)
 	 * @return bool
 	 */
-	public static function isMobile($ua = null)
+	public static function isMobile(?string $ua = null): bool
 	{
 		// Get the User-Agent header if the caller did not specify $ua.
 		if ($ua === null)
@@ -95,10 +95,10 @@ class UA
 	 * @param string $ua (optional)
 	 * @return bool
 	 */
-	public static function isTablet($ua = null)
+	public static function isTablet(?string $ua = null): bool
 	{
 		// Get the User-Agent header if the caller did not specify $ua.
-		$ua = $ua ?: (isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : null);
+		$ua = $ua ?: ($_SERVER['HTTP_USER_AGENT'] ?? null);
 
 		// If the User-Agent header is missing, it's probably not a tablet.
 		if (is_null($ua))
@@ -140,10 +140,10 @@ class UA
 	 * @param string $ua (optional)
 	 * @return bool
 	 */
-	public static function isRobot($ua = null)
+	public static function isRobot(?string $ua = null): bool
 	{
 		// Get the User-Agent header if the caller did not specify $ua.
-		$ua = $ua ?: (isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : null);
+		$ua = $ua ?: ($_SERVER['HTTP_USER_AGENT'] ?? null);
 
 		// If the User-Agent header is missing, it's probably not a robot.
 		if (is_null($ua))
@@ -183,10 +183,10 @@ class UA
 	 * @param string $header (optional)
 	 * @return string
 	 */
-	public static function getLocale($header = null)
+	public static function getLocale(?string $header = null): string
 	{
 		// Get the Accept-Language header if the caller did not specify $header.
-		$header = $header ?: (isset($_SERVER['HTTP_ACCEPT_LANGUAGE']) ? $_SERVER['HTTP_ACCEPT_LANGUAGE'] : 'en-US');
+		$header = $header ?: ($_SERVER['HTTP_ACCEPT_LANGUAGE'] ?? 'en-US');
 
 		// Return the first locale name found.
 		return preg_match('/^([a-z0-9_-]+)/i', $header, $matches) ? $matches[1] : 'en-US';
@@ -198,10 +198,10 @@ class UA
 	 * @param string $ua (optional)
 	 * @return object
 	 */
-	public static function getBrowserInfo($ua = null)
+	public static function getBrowserInfo(?string $ua = null): object
 	{
 		// Get the User-Agent header if the caller did not specify $ua.
-		$ua = $ua ?: (isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : null);
+		$ua = $ua ?: ($_SERVER['HTTP_USER_AGENT'] ?? null);
 
 		// Initialize the result.
 		$result = (object)array(
@@ -374,10 +374,10 @@ class UA
 	 * @param string $ua (optional)
 	 * @return string
 	 */
-	public static function encodeFilenameForDownload($filename, $ua = null)
+	public static function encodeFilenameForDownload(string $filename, ?string $ua = null): string
 	{
 		// Get the User-Agent header if the caller did not specify $ua.
-		$ua = $ua ?: (isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : null);
+		$ua = $ua ?: ($_SERVER['HTTP_USER_AGENT'] ?? null);
 
 		// Get the browser name and version.
 		$browser = self::getBrowserInfo($ua);
@@ -463,7 +463,7 @@ class UA
 	 * @param string $color_scheme
 	 * @return void
 	 */
-	public static function setColorScheme(string $color_scheme)
+	public static function setColorScheme(string $color_scheme): void
 	{
 		if (in_array($color_scheme, ['light', 'dark']))
 		{
diff --git a/common/framework/URL.php b/common/framework/URL.php
index 671d1ce57..92ba5d503 100644
--- a/common/framework/URL.php
+++ b/common/framework/URL.php
@@ -16,7 +16,7 @@ class URL
 	 * @param array $changes
 	 * @return string
 	 */
-	public static function getCurrentURL(array $changes = array())
+	public static function getCurrentURL(array $changes = []): string
 	{
 		$request_uri = preg_replace('/[<>"]/', '', isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : '/');
 		$url = self::getCurrentDomainURL($request_uri);
@@ -36,7 +36,7 @@ class URL
 	 * @param string $path
 	 * @return string
 	 */
-	public static function getCurrentDomainURL($path = '/')
+	public static function getCurrentDomainURL(string $path = '/'): string
 	{
 		$proto = \RX_SSL ? 'https://' : 'http://';
 		$host = isset($_SERVER['HTTP_HOST']) ? self::decodeIdna($_SERVER['HTTP_HOST']) : 'localhost';
@@ -49,7 +49,7 @@ class URL
 	 * @param string $url
 	 * @return string
 	 */
-	public static function getCanonicalURL($url)
+	public static function getCanonicalURL(string $url): string
 	{
 		if (preg_match('#^\.?/([^/]|$)#', $url) || !preg_match('#^(https?:|/)#', $url))
 		{
@@ -67,7 +67,7 @@ class URL
 	 * @param string $url
 	 * @return string|false
 	 */
-	public static function getDomainFromURL($url)
+	public static function getDomainFromURL(string $url)
 	{
 		$domain = @parse_url($url, \PHP_URL_HOST);
 		if ($domain === false || $domain === null)
@@ -86,7 +86,7 @@ class URL
 	 * @param string $url
 	 * @return bool
 	 */
-	public static function isInternalURL($url)
+	public static function isInternalURL(string $url): bool
 	{
 		$domain = self::getDomainFromURL($url);
 		if ($domain === false)
@@ -117,7 +117,7 @@ class URL
 	 * @param array $changes
 	 * @return string
 	 */
-	public static function modifyURL($url, array $changes = array())
+	public static function modifyURL(string $url, array $changes = []): string
 	{
 		$url = parse_url(self::getCanonicalURL($url));
 		$prefix = sprintf('%s://%s%s%s', $url['scheme'], $url['host'], (($url['port'] ?? '') ? (':' . $url['port']) : ''), $url['path']);
@@ -143,7 +143,7 @@ class URL
 	 * @param string $path
 	 * @return string|false
 	 */
-	public static function fromServerPath($path)
+	public static function fromServerPath(string $path)
 	{
 		$cleanpath = Filters\FilenameFilter::cleanPath($path);
 		if (substr($path, -1) === '/')
@@ -169,16 +169,17 @@ class URL
 	 * e.g. if the URL belongs to an external domain.
 	 *
 	 * @param string $url
-	 * @return string
+	 * @return string|false
 	 */
-	public static function toServerPath($url)
+	public static function toServerPath(string $url)
 	{
 		$url = self::getCanonicalURL($url);
 		if (!self::isInternalURL($url))
 		{
 			return false;
 		}
-		return Filters\FilenameFilter::cleanPath($_SERVER['DOCUMENT_ROOT'] . parse_url($url, \PHP_URL_PATH));
+		$root = $_SERVER['DOCUMENT_ROOT'] ?? rtrim(\RX_BASEDIR, '/');
+		return Filters\FilenameFilter::cleanPath($root . parse_url($url, \PHP_URL_PATH));
 	}
 
 	/**
@@ -187,7 +188,7 @@ class URL
 	 * @param string $url
 	 * @return string
 	 */
-	public static function encodeIdna($url)
+	public static function encodeIdna(string $url): string
 	{
 		if (preg_match('@[:/#]@', $url))
 		{
@@ -223,7 +224,7 @@ class URL
 	 * @param string $url
 	 * @return string
 	 */
-	public static function decodeIdna($url)
+	public static function decodeIdna(string $url): string
 	{
 		if (preg_match('@[:/#]@', $url))
 		{