diff --git a/src/TodoBySymfonyDeprecationRule.php b/src/TodoBySymfonyDeprecationRule.php
new file mode 100644
index 0000000..31392be
--- /dev/null
+++ b/src/TodoBySymfonyDeprecationRule.php
@@ -0,0 +1,120 @@
+<?php
+
+namespace staabm\PHPStanTodoBy;
+
+use Composer\InstalledVersions;
+use Composer\Semver\Comparator;
+use Composer\Semver\VersionParser;
+use PhpParser\Comment;
+use PhpParser\Node;
+use PHPStan\Analyser\Scope;
+use PHPStan\Internal\ComposerHelper;
+use PHPStan\Reflection\ReflectionProvider;
+use PHPStan\Rules\Rule;
+use PHPStan\Rules\RuleError;
+use PHPStan\Rules\RuleErrorBuilder;
+use PHPStan\Type\VerbosityLevel;
+use staabm\PHPStanTodoBy\utils\CommentMatcher;
+use staabm\PHPStanTodoBy\utils\ExpiredCommentErrorBuilder;
+use UnexpectedValueException;
+
+use function array_key_exists;
+use function in_array;
+use function is_array;
+use function is_string;
+use function strlen;
+use function trim;
+
+/**
+ * @implements Rule<Node\Expr\FuncCall>
+ */
+final class TodoBySymfonyDeprecationRule implements Rule
+{
+    private string $workingDirectory;
+
+    public function __construct(
+        string $workingDirectory
+    ) {
+        $this->workingDirectory = $workingDirectory;
+
+        // require the top level installed versions, so we don't mix it up with the one in phpstan.phar
+        $installedVersions = $this->workingDirectory . '/vendor/composer/InstalledVersions.php';
+        if (!class_exists(InstalledVersions::class, false) && is_readable($installedVersions)) {
+            require_once $installedVersions;
+        }
+    }
+
+    public function getNodeType(): string
+    {
+        return Node\Expr\FuncCall::class;
+    }
+
+    public function processNode(Node $node, Scope $scope): array
+    {
+        if (!($node->name instanceof Node\Name)) {
+            return [];
+        }
+
+        $args = $node->getArgs();
+        if (count($args) < 3) {
+            return [];
+        }
+
+        $functionName = strtolower($node->name->toString());
+        if ($functionName !== 'trigger_deprecation') {
+            return [];
+        }
+
+        $packageArgType = $scope->getType($args[0]->value);
+        $versionArgType = $scope->getType($args[1]->value);
+        $messageArgType = $scope->getType($args[2]->value);
+
+        $messages = $messageArgType->getConstantStrings();
+        if (count($messages) !== 1) {
+            return [];
+        }
+        $message = $messages[0]->getValue();
+
+        $errors = [];
+        foreach($packageArgType->getConstantStrings() as $package) {
+            foreach ($versionArgType->getConstantStrings() as $version) {
+
+                $satisfiesOrError = $this->satisfiesInstalledPackage($package->getValue(), $version->getValue());
+                if ($satisfiesOrError instanceof RuleError) {
+                    $errors[] = $satisfiesOrError;
+                    continue;
+                }
+                if (true !== $satisfiesOrError) {
+                    continue;
+                }
+
+                $errorMessage = 'Since %s %s: %s.';
+                $errors[] = sprintf($errorMessage, $package->getValue(), $version->getValue(), $message);
+            }
+        }
+
+        return $errors;
+    }
+
+    /**
+     * @return bool|\PHPStan\Rules\RuleError
+     */
+    private function satisfiesInstalledPackage(string $package, string $version)
+    {
+        $versionParser = new VersionParser();
+
+        // see https://getcomposer.org/doc/07-runtime.md#installed-versions
+        if (!InstalledVersions::isInstalled($package)) {
+            return false;
+        }
+
+        try {
+            return InstalledVersions::satisfies($versionParser, $package, '>='.$version);
+        } catch (UnexpectedValueException $e) {
+            return RuleErrorBuilder::message(
+                'Invalid version constraint "' . $version . '" for package "' . $package . '".',
+            )->build();
+        }
+    }
+
+}
diff --git a/tests/TodoBySymfonyDeprecationTest.php b/tests/TodoBySymfonyDeprecationTest.php
new file mode 100644
index 0000000..7e1f804
--- /dev/null
+++ b/tests/TodoBySymfonyDeprecationTest.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace staabm\PHPStanTodoBy\Tests;
+
+use PHPStan\Rules\Rule;
+use PHPStan\Testing\RuleTestCase;
+use staabm\PHPStanTodoBy\TodoBySymfonyDeprecationRule;
+use staabm\PHPStanTodoBy\TodoByVersionRule;
+use staabm\PHPStanTodoBy\utils\ExpiredCommentErrorBuilder;
+use staabm\PHPStanTodoBy\utils\GitTagFetcher;
+use staabm\PHPStanTodoBy\utils\ReferenceVersionFinder;
+
+/**
+ * @extends RuleTestCase<TodoBySymfonyDeprecationRule>
+ * @internal
+ */
+final class TodoBySymfonyDeprecationTest extends RuleTestCase
+{
+    protected function getRule(): Rule
+    {
+        return new TodoBySymfonyDeprecationRule(
+            dirname(__DIR__),
+        );
+    }
+
+    public function testRule(): void
+    {
+        $this->analyse([__DIR__ . '/data/sf-trigger-deprecation.php'], [
+            [
+                'Since phpunit/phpunit 9.5: Using this is deprecated. Use that instead..',
+                5
+            ]
+        ]);
+    }
+
+}
diff --git a/tests/data/sf-trigger-deprecation.php b/tests/data/sf-trigger-deprecation.php
new file mode 100644
index 0000000..3119bb1
--- /dev/null
+++ b/tests/data/sf-trigger-deprecation.php
@@ -0,0 +1,5 @@
+<?php
+
+namespace SymfonyDeprecations;
+
+trigger_deprecation('phpunit/phpunit', '9.5', 'Using this is deprecated. Use that instead.');