diff --git a/src/Changes.php b/src/Changes.php
index f4f41cdd..23bd5bc5 100644
--- a/src/Changes.php
+++ b/src/Changes.php
@@ -7,11 +7,13 @@
 use Countable;
 use Generator;
 use IteratorAggregate;
+use Psl\Dict;
+use Psl\Iter;
 use Traversable;
 
-use function count;
-use function iterator_to_array;
-
+/**
+ * @implements IteratorAggregate<int, Change>
+ */
 final class Changes implements IteratorAggregate, Countable
 {
     /** @var Change[] */
@@ -99,6 +101,6 @@ public function getIterator(): iterable
 
     public function count(): int
     {
-        return count(iterator_to_array($this));
+        return Iter\count(Dict\from_iterable($this));
     }
 }
diff --git a/src/DetectChanges/BCBreak/ClassBased/ConstantChanged.php b/src/DetectChanges/BCBreak/ClassBased/ConstantChanged.php
index 76c083c8..5f5e2e21 100644
--- a/src/DetectChanges/BCBreak/ClassBased/ConstantChanged.php
+++ b/src/DetectChanges/BCBreak/ClassBased/ConstantChanged.php
@@ -4,15 +4,14 @@
 
 namespace Roave\BackwardCompatibility\DetectChanges\BCBreak\ClassBased;
 
+use Psl\Dict;
+use Psl\Vec;
 use Roave\BackwardCompatibility\Change;
 use Roave\BackwardCompatibility\Changes;
 use Roave\BackwardCompatibility\DetectChanges\BCBreak\ClassConstantBased\ClassConstantBased;
 use Roave\BetterReflection\Reflection\ReflectionClass;
 use Roave\BetterReflection\Reflection\ReflectionClassConstant;
 
-use function array_intersect_key;
-use function array_keys;
-
 final class ConstantChanged implements ClassBased
 {
     private ClassConstantBased $checkConstant;
@@ -38,7 +37,7 @@ public function __invoke(ReflectionClass $fromClass, ReflectionClass $toClass):
      */
     private function checkSymbols(array $from, array $to): iterable
     {
-        foreach (array_keys(array_intersect_key($from, $to)) as $name) {
+        foreach (Vec\keys(Dict\intersect_by_key($from, $to)) as $name) {
             yield from $this->checkConstant->__invoke($from[$name], $to[$name]);
         }
     }
diff --git a/src/DetectChanges/BCBreak/ClassBased/PropertyChanged.php b/src/DetectChanges/BCBreak/ClassBased/PropertyChanged.php
index 7893add4..410e2138 100644
--- a/src/DetectChanges/BCBreak/ClassBased/PropertyChanged.php
+++ b/src/DetectChanges/BCBreak/ClassBased/PropertyChanged.php
@@ -4,15 +4,14 @@
 
 namespace Roave\BackwardCompatibility\DetectChanges\BCBreak\ClassBased;
 
+use Psl\Dict;
+use Psl\Vec;
 use Roave\BackwardCompatibility\Change;
 use Roave\BackwardCompatibility\Changes;
 use Roave\BackwardCompatibility\DetectChanges\BCBreak\PropertyBased\PropertyBased;
 use Roave\BetterReflection\Reflection\ReflectionClass;
 use Roave\BetterReflection\Reflection\ReflectionProperty;
 
-use function array_intersect_key;
-use function array_keys;
-
 final class PropertyChanged implements ClassBased
 {
     private PropertyBased $checkProperty;
@@ -38,7 +37,7 @@ public function __invoke(ReflectionClass $fromClass, ReflectionClass $toClass):
      */
     private function checkSymbols(array $from, array $to): iterable
     {
-        foreach (array_keys(array_intersect_key($from, $to)) as $name) {
+        foreach (Vec\keys(Dict\intersect_by_key($from, $to)) as $name) {
             yield from $this->checkProperty->__invoke($from[$name], $to[$name]);
         }
     }
diff --git a/src/DetectChanges/Variance/TypeIsContravariant.php b/src/DetectChanges/Variance/TypeIsContravariant.php
index 185e74b5..31ba0dff 100644
--- a/src/DetectChanges/Variance/TypeIsContravariant.php
+++ b/src/DetectChanges/Variance/TypeIsContravariant.php
@@ -4,11 +4,10 @@
 
 namespace Roave\BackwardCompatibility\DetectChanges\Variance;
 
-use Roave\BackwardCompatibility\Support\ArrayHelpers;
+use Psl\Iter;
+use Psl\Str;
 use Roave\BetterReflection\Reflection\ReflectionType;
 
-use function strtolower;
-
 /**
  * This is a simplistic contravariant type check. A more appropriate approach would be to
  * have a `$type->includes($otherType)` check with actual types represented as value objects,
@@ -37,7 +36,7 @@ public function __invoke(
         $typeAsString         = $type->__toString();
         $comparedTypeAsString = $comparedType->__toString();
 
-        if (strtolower($typeAsString) === strtolower($comparedTypeAsString)) {
+        if (Str\lowercase($typeAsString) === Str\lowercase($comparedTypeAsString)) {
             return true;
         }
 
@@ -70,9 +69,6 @@ public function __invoke(
             return $typeReflectionClass->implementsInterface($comparedTypeAsString);
         }
 
-        return ArrayHelpers::stringArrayContainsString(
-            $comparedTypeAsString,
-            $typeReflectionClass->getParentClassNames()
-        );
+        return Iter\contains($typeReflectionClass->getParentClassNames(), $comparedTypeAsString);
     }
 }
diff --git a/src/DetectChanges/Variance/TypeIsCovariant.php b/src/DetectChanges/Variance/TypeIsCovariant.php
index c2f0eea3..4c819c44 100644
--- a/src/DetectChanges/Variance/TypeIsCovariant.php
+++ b/src/DetectChanges/Variance/TypeIsCovariant.php
@@ -4,12 +4,11 @@
 
 namespace Roave\BackwardCompatibility\DetectChanges\Variance;
 
-use Roave\BackwardCompatibility\Support\ArrayHelpers;
+use Psl\Iter;
+use Psl\Str;
 use Roave\BetterReflection\Reflection\ReflectionType;
 use Traversable;
 
-use function strtolower;
-
 /**
  * This is a simplistic covariant type check. A more appropriate approach would be to
  * have a `$type->includes($otherType)` check with actual types represented as value objects,
@@ -39,7 +38,7 @@ public function __invoke(
         $typeAsString         = $type->__toString();
         $comparedTypeAsString = $comparedType->__toString();
 
-        if (strtolower($typeAsString) === strtolower($comparedTypeAsString)) {
+        if (Str\lowercase($typeAsString) === Str\lowercase($comparedTypeAsString)) {
             return true;
         }
 
@@ -81,9 +80,6 @@ public function __invoke(
             return $comparedTypeReflectionClass->implementsInterface($typeAsString);
         }
 
-        return ArrayHelpers::stringArrayContainsString(
-            $typeAsString,
-            $comparedTypeReflectionClass->getParentClassNames()
-        );
+        return Iter\contains($comparedTypeReflectionClass->getParentClassNames(), $typeAsString);
     }
 }
diff --git a/src/Formatter/MarkdownPipedToSymfonyConsoleFormatter.php b/src/Formatter/MarkdownPipedToSymfonyConsoleFormatter.php
index 85e9d95f..2932c555 100644
--- a/src/Formatter/MarkdownPipedToSymfonyConsoleFormatter.php
+++ b/src/Formatter/MarkdownPipedToSymfonyConsoleFormatter.php
@@ -4,17 +4,12 @@
 
 namespace Roave\BackwardCompatibility\Formatter;
 
+use Psl\Str;
+use Psl\Vec;
 use Roave\BackwardCompatibility\Change;
 use Roave\BackwardCompatibility\Changes;
 use Symfony\Component\Console\Output\OutputInterface;
 
-use function array_filter;
-use function array_map;
-use function implode;
-use function iterator_to_array;
-use function str_replace;
-use function trim;
-
 final class MarkdownPipedToSymfonyConsoleFormatter implements OutputFormatter
 {
     private OutputInterface $output;
@@ -26,41 +21,45 @@ public function __construct(OutputInterface $output)
 
     public function write(Changes $changes): void
     {
-        $arrayOfChanges = iterator_to_array($changes);
+        $arrayOfChanges = Vec\values($changes);
 
         $this->output->writeln(
             "# Added\n"
-            . implode('', $this->convertFilteredChangesToMarkdownBulletList(
+            . Str\join($this->convertFilteredChangesToMarkdownBulletList(
                 static function (Change $change): bool {
                     return $change->isAdded();
                 },
                 ...$arrayOfChanges
-            ))
+            ), '')
             . "\n# Changed\n"
-            . implode('', $this->convertFilteredChangesToMarkdownBulletList(
+            . Str\join($this->convertFilteredChangesToMarkdownBulletList(
                 static function (Change $change): bool {
                     return $change->isChanged();
                 },
                 ...$arrayOfChanges
-            ))
+            ), '')
             . "\n# Removed\n"
-            . implode('', $this->convertFilteredChangesToMarkdownBulletList(
+            . Str\join($this->convertFilteredChangesToMarkdownBulletList(
                 static function (Change $change): bool {
                     return $change->isRemoved();
                 },
                 ...$arrayOfChanges
-            ))
+            ), '')
         );
     }
 
-    /** @return string[] */
+    /**
+     * @param callable(Change): bool $filterFunction
+     *
+     * @return list<string>
+     */
     private function convertFilteredChangesToMarkdownBulletList(callable $filterFunction, Change ...$changes): array
     {
-        return array_map(
+        return Vec\map(
+            Vec\filter($changes, $filterFunction),
             static function (Change $change): string {
-                return ' - ' . str_replace(['ADDED: ', 'CHANGED: ', 'REMOVED: '], '', trim($change->__toString())) . "\n";
-            },
-            array_filter($changes, $filterFunction)
+                return ' - ' . Str\replace_every(Str\trim($change->__toString()), ['ADDED: ' => '', 'CHANGED: ' => '', 'REMOVED: ' => '']) . "\n";
+            }
         );
     }
 }
diff --git a/src/Support/ArrayHelpers.php b/src/Support/ArrayHelpers.php
deleted file mode 100644
index f11dc9fe..00000000
--- a/src/Support/ArrayHelpers.php
+++ /dev/null
@@ -1,28 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Roave\BackwardCompatibility\Support;
-
-use InvalidArgumentException;
-
-use function in_array;
-
-/**
- * @internal this is a support class of this library, and should NOT be used outside of it
- */
-final class ArrayHelpers
-{
-    /**
-     * Yes, this is just a very pedantic version of `in_array()`, written to avoid mutations and
-     * designed to throw an exception if `$arrayOfStrings` is not a `string[]` as requested.
-     *
-     * @param string[] $arrayOfStrings
-     *
-     * @throws InvalidArgumentException
-     */
-    public static function stringArrayContainsString(string $value, array $arrayOfStrings): bool
-    {
-        return in_array($value, $arrayOfStrings);
-    }
-}
diff --git a/test/unit/Support/ArrayHelpersTest.php b/test/unit/Support/ArrayHelpersTest.php
deleted file mode 100644
index 15041a66..00000000
--- a/test/unit/Support/ArrayHelpersTest.php
+++ /dev/null
@@ -1,70 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace RoaveTest\BackwardCompatibility\Support;
-
-use PHPUnit\Framework\TestCase;
-use Roave\BackwardCompatibility\Support\ArrayHelpers;
-
-/**
- * @covers \Roave\BackwardCompatibility\Support\ArrayHelpers
- */
-final class ArrayHelpersTest extends TestCase
-{
-    /**
-     * @param string[] $array
-     *
-     * @dataProvider stringArrayContainsStringValidValues
-     */
-    public function testInclusion(string $value, array $array, bool $expected): void
-    {
-        self::assertSame($expected, ArrayHelpers::stringArrayContainsString($value, $array));
-    }
-
-    /**
-     * @return array<int, array<int, string|array<int, string>|bool>>
-     *
-     * @psalm-return array<int, array{0: string, 1: list<string>, 2: bool}>
-     */
-    public function stringArrayContainsStringValidValues(): array
-    {
-        return [
-            [
-                '',
-                [],
-                false,
-            ],
-            [
-                '',
-                [''],
-                true,
-            ],
-            [
-                '0',
-                [''],
-                false,
-            ],
-            [
-                '',
-                ['0'],
-                false,
-            ],
-            [
-                'foo',
-                ['foo', 'bar', 'baz'],
-                true,
-            ],
-            [
-                'foo',
-                ['bar', 'baz'],
-                false,
-            ],
-            [
-                'foo',
-                ['foo', 'foo', 'foo'],
-                true,
-            ],
-        ];
-    }
-}