diff --git a/README.md b/README.md
index 9924920..9749943 100644
--- a/README.md
+++ b/README.md
@@ -138,6 +138,10 @@ function doesAThing(array $data): int {
 #### SlevomatCodingStandard.Functions.StaticClosure
 #### SlevomatCodingStandard.Functions.UnusedInheritedVariablePassedToClosure
 #### SlevomatCodingStandard.Namespaces.AlphabeticallySortedUses
+#### SlevomatCodingStandard.Namespaces.FullyQualifiedGlobalFunctions
+
+PHPStorm can be configured with Editor -> General -> Auto Import: _Function_: `Prefer FQN`
+
 #### SlevomatCodingStandard.TypeHints.DeclareStrictTypes
 #### SlevomatCodingStandard.TypeHints.ReturnTypeHint
 #### SlevomatCodingStandard.TypeHints.ReturnTypeHintSpacing
diff --git a/composer.json b/composer.json
index 60f20c4..ec4d4e8 100644
--- a/composer.json
+++ b/composer.json
@@ -4,18 +4,18 @@
     "homepage": "https://github.com/previousnext/coding-standard",
     "keywords": ["drupal", "phpcs"],
     "require": {
-        "php": "^8.0",
+        "php": "^8.1",
         "dealerdirect/phpcodesniffer-composer-installer": "^1.0.0",
         "drupal/coder": "^8.3.24",
-        "slevomat/coding-standard": "^8.13.2",
-        "squizlabs/php_codesniffer": "^3.7.1"
+        "slevomat/coding-standard": "^8.15.0",
+        "squizlabs/php_codesniffer": "^3.10.1"
     },
     "require-dev": {
-        "phpstan/extension-installer": "^1.2",
-        "phpstan/phpstan": "^1.9.4",
-        "phpstan/phpstan-deprecation-rules": "^1.1.1",
-        "phpstan/phpstan-strict-rules": "^1.4.4",
-        "phpunit/phpunit": "^9.5.27"
+        "phpstan/extension-installer": "^1.3.1",
+        "phpstan/phpstan": "^1.11.3",
+        "phpstan/phpstan-deprecation-rules": "^1.2.0",
+        "phpstan/phpstan-strict-rules": "^1.6.0",
+        "phpunit/phpunit": "^9.6.19"
     },
     "license": "MIT",
     "autoload": {
diff --git a/tests/Sniffs/FullyQualifiedGlobalFunctionsTest.php b/tests/Sniffs/FullyQualifiedGlobalFunctionsTest.php
new file mode 100644
index 0000000..e3bd05b
--- /dev/null
+++ b/tests/Sniffs/FullyQualifiedGlobalFunctionsTest.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PreviousNext\CodingStandard\Tests\Sniffs;
+
+use SlevomatCodingStandard\Sniffs\Namespaces\FullyQualifiedGlobalFunctionsSniff;
+
+/**
+ * @covers \SlevomatCodingStandard\Sniffs\Namespaces\FullyQualifiedGlobalFunctionsSniff
+ */
+final class FullyQualifiedGlobalFunctionsTest extends Base {
+
+  public function testNoError(): void {
+    $report = self::checkFile(__DIR__ . '/fixtures/FullyQualifiedGlobalFunctionsNoError.php');
+    self::assertNoSniffErrorInFile($report);
+  }
+
+  public function testError(): void {
+    $report = self::checkFile(__DIR__ . '/fixtures/FullyQualifiedGlobalFunctionsError.php');
+    self::assertSame(1, $report->getErrorCount());
+    self::assertSniffError($report, 7, FullyQualifiedGlobalFunctionsSniff::CODE_NON_FULLY_QUALIFIED);
+  }
+
+  protected static function getSniffName(): string {
+    return 'SlevomatCodingStandard.Namespaces.FullyQualifiedGlobalFunctions';
+  }
+
+}
diff --git a/tests/Sniffs/fixtures/FullyQualifiedGlobalFunctionsError.php b/tests/Sniffs/fixtures/FullyQualifiedGlobalFunctionsError.php
new file mode 100644
index 0000000..e3d61a6
--- /dev/null
+++ b/tests/Sniffs/fixtures/FullyQualifiedGlobalFunctionsError.php
@@ -0,0 +1,7 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Somewhere;
+
+echo strlen('Foo bar');
diff --git a/tests/Sniffs/fixtures/FullyQualifiedGlobalFunctionsNoError.php b/tests/Sniffs/fixtures/FullyQualifiedGlobalFunctionsNoError.php
new file mode 100644
index 0000000..a874ee1
--- /dev/null
+++ b/tests/Sniffs/fixtures/FullyQualifiedGlobalFunctionsNoError.php
@@ -0,0 +1,7 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Somewhere;
+
+echo \strlen('Foo bar');