diff --git a/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/Fixture/skip_dynamic_second_arg.php.inc b/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/Fixture/skip_dynamic_second_arg.php.inc
deleted file mode 100644
index 915922b780c..00000000000
--- a/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/Fixture/skip_dynamic_second_arg.php.inc
+++ /dev/null
@@ -1,14 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Rector\Tests\CodeQuality\Rector\FuncCall\SimplifyStrposLowerRector\Fixture;
-
-final class SkipDynamicSecondArg
-{
-    public function run(string $findMe)
-    {
-        $string = 'hey';
-        strpos(strtolower($string), $findMe);
-    }
-}
diff --git a/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/Fixture/skip_has_uppercase_second_arg.php.inc b/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/Fixture/skip_has_uppercase_second_arg.php.inc
deleted file mode 100644
index b9db29ab9e3..00000000000
--- a/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/Fixture/skip_has_uppercase_second_arg.php.inc
+++ /dev/null
@@ -1,14 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Rector\Tests\CodeQuality\Rector\FuncCall\SimplifyStrposLowerRector\Fixture;
-
-final class SkipHasUppercaseSecondArg
-{
-    public function run()
-    {
-        $string = 'hey';
-        strpos(strtolower($string), 'findME1');
-    }
-}
diff --git a/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/Fixture/strpos.php.inc b/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/Fixture/strpos.php.inc
deleted file mode 100644
index 0a29e087c7f..00000000000
--- a/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/Fixture/strpos.php.inc
+++ /dev/null
@@ -1,39 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Rector\Tests\CodeQuality\Rector\FuncCall\SimplifyStrposLowerRector\Fixture;
-
-final class Strpos
-{
-    public function run()
-    {
-        $string = 'hey';
-        strpos(strtolower($string), 'find-me');
-
-        $funcName = 'strpos';
-        $funcName(strtolower($string), 'find-me');
-    }
-}
-
-?>
------
-<?php
-
-declare(strict_types=1);
-
-namespace Rector\Tests\CodeQuality\Rector\FuncCall\SimplifyStrposLowerRector\Fixture;
-
-final class Strpos
-{
-    public function run()
-    {
-        $string = 'hey';
-        stripos($string, 'find-me');
-
-        $funcName = 'strpos';
-        $funcName(strtolower($string), 'find-me');
-    }
-}
-
-?>
diff --git a/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/SimplifyStrposLowerRectorTest.php b/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/SimplifyStrposLowerRectorTest.php
deleted file mode 100644
index 2068a172eba..00000000000
--- a/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/SimplifyStrposLowerRectorTest.php
+++ /dev/null
@@ -1,28 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Rector\Tests\CodeQuality\Rector\FuncCall\SimplifyStrposLowerRector;
-
-use Iterator;
-use PHPUnit\Framework\Attributes\DataProvider;
-use Rector\Testing\PHPUnit\AbstractRectorTestCase;
-
-final class SimplifyStrposLowerRectorTest extends AbstractRectorTestCase
-{
-    #[DataProvider('provideData')]
-    public function test(string $filePath): void
-    {
-        $this->doTestFile($filePath);
-    }
-
-    public static function provideData(): Iterator
-    {
-        return self::yieldFilesFromDirectory(__DIR__ . '/Fixture');
-    }
-
-    public function provideConfigFilePath(): string
-    {
-        return __DIR__ . '/config/configured_rule.php';
-    }
-}
diff --git a/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/config/configured_rule.php b/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/config/configured_rule.php
deleted file mode 100644
index 0f860e40ce9..00000000000
--- a/rules-tests/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector/config/configured_rule.php
+++ /dev/null
@@ -1,9 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-use Rector\CodeQuality\Rector\FuncCall\SimplifyStrposLowerRector;
-use Rector\Config\RectorConfig;
-
-return RectorConfig::configure()
-    ->withRules([SimplifyStrposLowerRector::class]);
diff --git a/rules/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector.php b/rules/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector.php
index 12bf2889ea3..d703a049feb 100644
--- a/rules/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector.php
+++ b/rules/CodeQuality/Rector/FuncCall/SimplifyStrposLowerRector.php
@@ -4,25 +4,19 @@
 
 namespace Rector\CodeQuality\Rector\FuncCall;
 
-use Nette\Utils\Strings;
 use PhpParser\Node;
 use PhpParser\Node\Expr\FuncCall;
-use PhpParser\Node\Name;
-use PhpParser\Node\Scalar\String_;
+use Rector\Configuration\Deprecation\Contract\DeprecatedInterface;
+use Rector\Exception\ShouldNotHappenException;
 use Rector\Rector\AbstractRector;
 use Rector\RuleDoc\CodeSample\CodeSample;
 use Rector\RuleDoc\RuleDefinition;
 
 /**
- * @see \Rector\Tests\CodeQuality\Rector\FuncCall\SimplifyStrposLowerRector\SimplifyStrposLowerRectorTest
+ * @deprecated This rule is deprecated, as it handles a niche strpos(strtolower()) case that is not part of the PHP upgrade path.
  */
-final class SimplifyStrposLowerRector extends AbstractRector
+final class SimplifyStrposLowerRector extends AbstractRector implements DeprecatedInterface
 {
-    /**
-     * @see https://regex101.com/r/Jokjt8/1
-     */
-    private const string UPPERCASE_REGEX = '#[A-Z]#';
-
     public function getRuleDefinition(): RuleDefinition
     {
         return new RuleDefinition(
@@ -44,42 +38,9 @@ public function getNodeTypes(): array
      */
     public function refactor(Node $node): ?Node
     {
-        if (! $this->isName($node, 'strpos')) {
-            return null;
-        }
-
-        if ($node->isFirstClassCallable()) {
-            return null;
-        }
-
-        $args = $node->getArgs();
-        if (! isset($args[0], $args[1])) {
-            return null;
-        }
-
-        $firstArg = $args[0];
-        if (! $firstArg->value instanceof FuncCall) {
-            return null;
-        }
-
-        $innerFuncCall = $firstArg->value;
-        if (! $this->isName($innerFuncCall, 'strtolower')) {
-            return null;
-        }
-
-        $secondArg = $args[1];
-        if (! $secondArg->value instanceof String_) {
-            return null;
-        }
-
-        if (Strings::match($secondArg->value->value, self::UPPERCASE_REGEX) !== null) {
-            return null;
-        }
-
-        // pop 1 level up
-        $node->args[0] = $innerFuncCall->getArgs()[0];
-        $node->name = new Name('stripos');
-
-        return $node;
+        throw new ShouldNotHappenException(sprintf(
+            '"%s" rule is deprecated, as it handles a niche strpos(strtolower()) case that is not part of the PHP upgrade path',
+            self::class
+        ));
     }
 }
diff --git a/src/Config/Level/CodeQualityLevel.php b/src/Config/Level/CodeQualityLevel.php
index 79f3e963fe0..17026f84675 100644
--- a/src/Config/Level/CodeQualityLevel.php
+++ b/src/Config/Level/CodeQualityLevel.php
@@ -42,7 +42,6 @@
 use Rector\CodeQuality\Rector\FuncCall\RemoveSoleValueSprintfRector;
 use Rector\CodeQuality\Rector\FuncCall\SimplifyFuncGetArgsCountRector;
 use Rector\CodeQuality\Rector\FuncCall\SimplifyInArrayValuesRector;
-use Rector\CodeQuality\Rector\FuncCall\SimplifyStrposLowerRector;
 use Rector\CodeQuality\Rector\FuncCall\SingleInArrayToCompareRector;
 use Rector\CodeQuality\Rector\FuncCall\SortCallLikeNamedArgsRector;
 use Rector\CodeQuality\Rector\Identical\BooleanNotIdenticalToNotIdenticalRector;
@@ -119,7 +118,6 @@ final class CodeQualityLevel
         SimplifyForeachToCoalescingRector::class,
         SimplifyFuncGetArgsCountRector::class,
         SimplifyInArrayValuesRector::class,
-        SimplifyStrposLowerRector::class,
         SimplifyArraySearchRector::class,
         SimplifyConditionsRector::class,
         SimplifyIfNotNullReturnRector::class,