diff --git a/system/CLI/CLI.php b/system/CLI/CLI.php
index ac1d929229c1..8a1d64e5a019 100644
--- a/system/CLI/CLI.php
+++ b/system/CLI/CLI.php
@@ -230,7 +230,7 @@ public static function prompt(string $field, $options = null, $validation = null
         }
 
         if (! is_array($validation)) {
-            $validation = ($validation !== null && $validation !== '') ? explode('|', $validation) : [];
+            $validation = ((string) $validation !== '') ? explode('|', $validation) : [];
         }
 
         if (is_string($options)) {
@@ -441,7 +441,7 @@ protected static function validate(string $field, string $value, $rules): bool
      */
     public static function print(string $text = '', ?string $foreground = null, ?string $background = null)
     {
-        if ($foreground !== null || $background !== null) {
+        if ((string) $foreground !== '' || (string) $background !== '') {
             $text = static::color($text, $foreground, $background);
         }
 
@@ -457,7 +457,7 @@ public static function print(string $text = '', ?string $foreground = null, ?str
      */
     public static function write(string $text = '', ?string $foreground = null, ?string $background = null)
     {
-        if ($foreground !== null || $background !== null) {
+        if ((string) $foreground !== '' || (string) $background !== '') {
             $text = static::color($text, $foreground, $background);
         }
 
@@ -480,7 +480,7 @@ public static function error(string $text, string $foreground = 'light_red', ?st
         $stdout            = static::$isColored;
         static::$isColored = static::hasColorSupport(STDERR);
 
-        if ($foreground !== '' || $background !== null) {
+        if ($foreground !== '' || (string) $background !== '') {
             $text = static::color($text, $foreground, $background);
         }
 
@@ -589,7 +589,7 @@ public static function color(string $text, string $foreground, ?string $backgrou
             throw CLIException::forInvalidColor('foreground', $foreground);
         }
 
-        if ($background !== null && ! array_key_exists($background, static::$background_colors)) {
+        if ((string) $background !== '' && ! array_key_exists($background, static::$background_colors)) {
             throw CLIException::forInvalidColor('background', $background);
         }
 
@@ -637,7 +637,7 @@ private static function getColoredText(string $text, string $foreground, ?string
     {
         $string = "\033[" . static::$foreground_colors[$foreground] . 'm';
 
-        if ($background !== null) {
+        if ((string) $background !== '') {
             $string .= "\033[" . static::$background_colors[$background] . 'm';
         }
 
@@ -654,7 +654,7 @@ private static function getColoredText(string $text, string $foreground, ?string
      */
     public static function strlen(?string $string): int
     {
-        if ($string === null) {
+        if ((string) $string === '') {
             return 0;
         }
 
@@ -835,7 +835,7 @@ public static function showProgress($thisStep = 1, int $totalSteps = 10)
      */
     public static function wrap(?string $string = null, int $max = 0, int $padLeft = 0): string
     {
-        if ($string === null || $string === '') {
+        if ((string) $string === '') {
             return '';
         }
 
diff --git a/system/Common.php b/system/Common.php
index 996658e6db1e..10c80ea0b7ea 100644
--- a/system/Common.php
+++ b/system/Common.php
@@ -75,7 +75,7 @@ function cache(?string $key = null)
         $cache = service('cache');
 
         // No params - return cache object
-        if ($key === null) {
+        if ((string) $key === '') {
             return $cache;
         }
 
@@ -289,7 +289,7 @@ function csrf_hash(): string
      */
     function csrf_field(?string $id = null): string
     {
-        return '<input type="hidden"' . ($id !== null ? ' id="' . esc($id, 'attr') . '"' : '') . ' name="' . csrf_token() . '" value="' . csrf_hash() . '"' . _solidus() . '>';
+        return '<input type="hidden"' . ((string) $id !== '' ? ' id="' . esc($id, 'attr') . '"' : '') . ' name="' . csrf_token() . '" value="' . csrf_hash() . '"' . _solidus() . '>';
     }
 }
 
@@ -301,7 +301,7 @@ function csrf_field(?string $id = null): string
      */
     function csrf_meta(?string $id = null): string
     {
-        return '<meta' . ($id !== null ? ' id="' . esc($id, 'attr') . '"' : '') . ' name="' . csrf_header() . '" content="' . csrf_hash() . '"' . _solidus() . '>';
+        return '<meta' . ((string) $id !== '' ? ' id="' . esc($id, 'attr') . '"' : '') . ' name="' . csrf_header() . '" content="' . csrf_hash() . '"' . _solidus() . '>';
     }
 }
 
@@ -441,7 +441,7 @@ function esc($data, string $context = 'html', ?string $encoding = null)
                 $escaper = new Escaper($encoding);
             }
 
-            if ($encoding !== null && $escaper->getEncoding() !== $encoding) {
+            if ((string) $encoding !== '' && $escaper->getEncoding() !== $encoding) {
                 $escaper = new Escaper($encoding);
             }
 
@@ -739,13 +739,13 @@ function lang(string $line, array $args = [], ?string $locale = null)
         // Get active locale
         $activeLocale = $language->getLocale();
 
-        if ($locale !== null && $locale !== $activeLocale) {
+        if ((string) $locale !== '' && $locale !== $activeLocale) {
             $language->setLocale($locale);
         }
 
         $lines = $language->getLine($line, $args);
 
-        if ($locale !== null && $locale !== $activeLocale) {
+        if ((string) $locale !== '' && $locale !== $activeLocale) {
             // Reset to active locale
             $language->setLocale($activeLocale);
         }
@@ -849,7 +849,7 @@ function redirect(?string $route = null): RedirectResponse
     {
         $response = service('redirectresponse');
 
-        if ($route !== null) {
+        if ((string) $route !== '') {
             return $response->route($route);
         }
 
@@ -1012,7 +1012,7 @@ function single_service(string $name, ...$params): ?object
     {
         $service = Services::serviceExists($name);
 
-        if ($service === null) {
+        if ((string) $service === '') {
             // The service is not defined anywhere so just return.
             return null;
         }
@@ -1128,7 +1128,7 @@ function timer(?string $name = null, ?callable $callable = null)
     {
         $timer = service('timer');
 
-        if ($name === null) {
+        if ((string) $name === '') {
             return $timer;
         }
 
diff --git a/system/Database/MigrationRunner.php b/system/Database/MigrationRunner.php
index 4a39f13562e8..d8b2896bfec6 100644
--- a/system/Database/MigrationRunner.php
+++ b/system/Database/MigrationRunner.php
@@ -161,7 +161,7 @@ public function latest(?string $group = null)
 
         $this->ensureTable();
 
-        if ($group !== null) {
+        if ((string) $group !== '') {
             $this->groupFilter = $group;
             $this->setGroup($group);
         }
@@ -326,7 +326,7 @@ public function force(string $path, string $namespace, ?string $group = null)
 
         $this->ensureTable();
 
-        if ($group !== null) {
+        if ((string) $group !== '') {
             $this->groupFilter = $group;
             $this->setGroup($group);
         }
diff --git a/system/Database/MySQLi/Connection.php b/system/Database/MySQLi/Connection.php
index c5a5645b17f8..8b165b870ae0 100644
--- a/system/Database/MySQLi/Connection.php
+++ b/system/Database/MySQLi/Connection.php
@@ -395,7 +395,7 @@ protected function _listTables(bool $prefixLimit = false, ?string $tableName = n
     {
         $sql = 'SHOW TABLES FROM ' . $this->escapeIdentifier($this->database);
 
-        if ($tableName !== null) {
+        if ((string) $tableName !== '') {
             return $sql . ' LIKE ' . $this->escape($tableName);
         }
 
diff --git a/system/Database/SQLite3/Connection.php b/system/Database/SQLite3/Connection.php
index 408fd46d14f0..577e4b24ab76 100644
--- a/system/Database/SQLite3/Connection.php
+++ b/system/Database/SQLite3/Connection.php
@@ -194,7 +194,7 @@ protected function _escapeString(string $str): string
      */
     protected function _listTables(bool $prefixLimit = false, ?string $tableName = null): string
     {
-        if ($tableName !== null) {
+        if ((string) $tableName !== '') {
             return 'SELECT "NAME" FROM "SQLITE_MASTER" WHERE "TYPE" = \'table\''
                    . ' AND "NAME" NOT LIKE \'sqlite!_%\' ESCAPE \'!\''
                    . ' AND "NAME" LIKE ' . $this->escape($tableName);
diff --git a/system/Filters/Filters.php b/system/Filters/Filters.php
index 58a2b0669764..fd252fe1fa26 100644
--- a/system/Filters/Filters.php
+++ b/system/Filters/Filters.php
@@ -557,7 +557,7 @@ public function enableFilters(array $names, string $when = 'before')
      */
     public function getArguments(?string $key = null)
     {
-        return $key === null ? $this->arguments : $this->arguments[$key];
+        return ((string) $key === '') ? $this->arguments : $this->arguments[$key];
     }
 
     // --------------------------------------------------------------------
diff --git a/system/HTTP/UserAgent.php b/system/HTTP/UserAgent.php
index 88dd56553e91..ec4d17438284 100644
--- a/system/HTTP/UserAgent.php
+++ b/system/HTTP/UserAgent.php
@@ -125,7 +125,7 @@ public function isBrowser(?string $key = null): bool
         }
 
         // No need to be specific, it's a browser
-        if ($key === null) {
+        if ((string) $key === '') {
             return true;
         }
 
@@ -143,7 +143,7 @@ public function isRobot(?string $key = null): bool
         }
 
         // No need to be specific, it's a robot
-        if ($key === null) {
+        if ((string) $key === '') {
             return true;
         }
 
@@ -161,7 +161,7 @@ public function isMobile(?string $key = null): bool
         }
 
         // No need to be specific, it's a mobile
-        if ($key === null) {
+        if ((string) $key === '') {
             return true;
         }
 
diff --git a/system/Model.php b/system/Model.php
index bdbaf45d7629..98e3be0b1f68 100644
--- a/system/Model.php
+++ b/system/Model.php
@@ -690,7 +690,7 @@ public function builder(?string $table = null)
         // Check for an existing Builder
         if ($this->builder instanceof BaseBuilder) {
             // Make sure the requested table matches the builder
-            if ($table !== null && $this->builder->getTable() !== $table) {
+            if ((string) $table !== '' && $this->builder->getTable() !== $table) {
                 return $this->db->table($table);
             }
 
@@ -704,7 +704,7 @@ public function builder(?string $table = null)
             throw ModelException::forNoPrimaryKey(static::class);
         }
 
-        $table = ($table === null || $table === '') ? $this->table : $table;
+        $table = ((string) $table === '') ? $this->table : $table;
 
         // Ensure we have a good db connection
         if (! $this->db instanceof BaseConnection) {
diff --git a/system/Router/AutoRouter.php b/system/Router/AutoRouter.php
index 39665afa6747..ce40f5cdc406 100644
--- a/system/Router/AutoRouter.php
+++ b/system/Router/AutoRouter.php
@@ -244,7 +244,7 @@ private function isValidSegment(string $segment): bool
      */
     public function setDirectory(?string $dir = null, bool $append = false, bool $validate = true)
     {
-        if ($dir === null || $dir === '') {
+        if ((string) $dir === '') {
             $this->directory = null;
 
             return;
@@ -260,7 +260,7 @@ public function setDirectory(?string $dir = null, bool $append = false, bool $va
             }
         }
 
-        if (! $append || ($this->directory === null || $this->directory === '')) {
+        if (! $append || ((string) $this->directory === '')) {
             $this->directory = trim($dir, '/') . '/';
         } else {
             $this->directory .= trim($dir, '/') . '/';
@@ -275,7 +275,7 @@ public function setDirectory(?string $dir = null, bool $append = false, bool $va
      */
     public function directory(): string
     {
-        return ($this->directory !== null && $this->directory !== '') ? $this->directory : '';
+        return ((string) $this->directory !== '') ? $this->directory : '';
     }
 
     private function controllerName(): string
diff --git a/system/Router/RouteCollection.php b/system/Router/RouteCollection.php
index 52e9eb8073bd..2dbaba05e4cd 100644
--- a/system/Router/RouteCollection.php
+++ b/system/Router/RouteCollection.php
@@ -560,7 +560,7 @@ public function shouldAutoRoute(): bool
      */
     public function getRoutes(?string $verb = null, bool $includeWildcard = true): array
     {
-        if ($verb === null || $verb === '') {
+        if ((string) $verb === '') {
             $verb = $this->getHTTPVerb();
         }
 
@@ -609,7 +609,7 @@ public function getRoutesOptions(?string $from = null, ?string $verb = null): ar
     {
         $options = $this->loadRoutesOptions($verb);
 
-        return $from !== null ? $options[$from] ?? [] : $options;
+        return ((string) $from !== '') ? $options[$from] ?? [] : $options;
     }
 
     /**
@@ -1416,14 +1416,14 @@ private function replaceLocale(string $route, ?string $locale = null): string
         }
 
         // Check invalid locale
-        if ($locale !== null) {
+        if ((string) $locale !== '') {
             $config = config(App::class);
             if (! in_array($locale, $config->supportedLocales, true)) {
                 $locale = null;
             }
         }
 
-        if ($locale === null) {
+        if ((string) $locale === '') {
             $locale = service('request')->getLocale();
         }