diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ce6f607..340fdf4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,11 +12,12 @@ jobs:
           # - windows-latest # Disabled - apparently checkouts have \r\n which breaks phpcs
           - macos-latest
         php-versions:
-          - '7.2'
-          - '7.3'
           - '7.4'
           - '8.0'
           - '8.1'
+          - '8.2'
+          - '8.3'
+          - '8.4'
     name: PHP ${{ matrix.php-versions }} Test on ${{ matrix.operating-system }}
     steps:
     - name: Checkout
@@ -39,3 +40,6 @@ jobs:
 
     - name: Unit tests
       run: ./vendor/bin/phpunit
+
+    - name: PHPStan
+      run: ./vendor/bin/phpstan analyze
diff --git a/composer.json b/composer.json
index 2c40aaa..ae9c8a9 100644
--- a/composer.json
+++ b/composer.json
@@ -19,7 +19,8 @@
     "require-dev": {
         "phpunit/phpunit": "^8.5",
         "php-coveralls/php-coveralls": "*",
-        "squizlabs/php_codesniffer": "3.*"
+        "squizlabs/php_codesniffer": "3.*",
+        "phpstan/phpstan": "^2.0"
     },
     "suggest": {
         "ext-gmp": "Required for optimized binomial calculations (also requires PHP >= 7.3)"
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
new file mode 100644
index 0000000..7df3b82
--- /dev/null
+++ b/phpstan-baseline.neon
@@ -0,0 +1,7 @@
+parameters:
+	ignoreErrors:
+		-
+			message: '#^Unsafe usage of new static\(\)\.$#'
+			identifier: new.static
+			count: 1
+			path: src/Matchers/DictionaryMatch.php
diff --git a/phpstan.neon b/phpstan.neon
new file mode 100644
index 0000000..2b8bf25
--- /dev/null
+++ b/phpstan.neon
@@ -0,0 +1,8 @@
+includes:
+	- phpstan-baseline.neon
+
+parameters:
+	level: 0
+	paths:
+		- src
+		- test
diff --git a/src/Matchers/BaseMatch.php b/src/Matchers/BaseMatch.php
index 527dbc5..97f77d3 100644
--- a/src/Matchers/BaseMatch.php
+++ b/src/Matchers/BaseMatch.php
@@ -4,7 +4,6 @@
 
 namespace ZxcvbnPhp\Matchers;
 
-use JetBrains\PhpStorm\ArrayShape;
 use ZxcvbnPhp\Math\Binomial;
 use ZxcvbnPhp\Scorer;
 
@@ -48,10 +47,8 @@ public function __construct(string $password, int $begin, int $end, string $toke
      *
      * @param  bool $isSoleMatch
      *   Whether this is the only match in the password
-     * @return array
-     *   Associative array with warning (string) and suggestions (array of strings)
+     * @return array{'warning': string, "suggestions": string[]}
      */
-    #[ArrayShape(['warning' => 'string', 'suggestions' => 'string[]'])]
     abstract public function getFeedback(bool $isSoleMatch): array;
 
     /**
diff --git a/src/Matchers/Bruteforce.php b/src/Matchers/Bruteforce.php
index cba7bcc..8e99092 100644
--- a/src/Matchers/Bruteforce.php
+++ b/src/Matchers/Bruteforce.php
@@ -4,7 +4,6 @@
 
 namespace ZxcvbnPhp\Matchers;
 
-use JetBrains\PhpStorm\ArrayShape;
 use ZxcvbnPhp\Scorer;
 
 /**
@@ -13,7 +12,7 @@
  *
  * Intentionally not named with Match suffix to prevent autoloading from Matcher.
  */
-class Bruteforce extends BaseMatch
+final class Bruteforce extends BaseMatch
 {
     public const BRUTEFORCE_CARDINALITY = 10;
 
@@ -32,7 +31,9 @@ public static function match(string $password, array $userInputs = []): array
     }
 
 
-    #[ArrayShape(['warning' => 'string', 'suggestions' => 'string[]'])]
+    /**
+     * @return array{'warning': string, "suggestions": string[]}
+     */
     public function getFeedback(bool $isSoleMatch): array
     {
         return [
diff --git a/src/Matchers/DateMatch.php b/src/Matchers/DateMatch.php
index f3fdcd9..c67bffe 100644
--- a/src/Matchers/DateMatch.php
+++ b/src/Matchers/DateMatch.php
@@ -4,10 +4,9 @@
 
 namespace ZxcvbnPhp\Matchers;
 
-use JetBrains\PhpStorm\ArrayShape;
 use ZxcvbnPhp\Matcher;
 
-class DateMatch extends BaseMatch
+final class DateMatch extends BaseMatch
 {
     public const NUM_YEARS = 119; // Years match against 1900 - 2019
     public const NUM_MONTHS = 12;
@@ -108,7 +107,9 @@ public static function match(string $password, array $userInputs = []): array
         return $matches;
     }
 
-    #[ArrayShape(['warning' => 'string', 'suggestions' => 'string[]'])]
+    /**
+     * @return array{'warning': string, "suggestions": string[]}
+     */
     public function getFeedback(bool $isSoleMatch): array
     {
         return [
diff --git a/src/Matchers/DictionaryMatch.php b/src/Matchers/DictionaryMatch.php
index b936681..334ac90 100644
--- a/src/Matchers/DictionaryMatch.php
+++ b/src/Matchers/DictionaryMatch.php
@@ -4,7 +4,6 @@
 
 namespace ZxcvbnPhp\Matchers;
 
-use JetBrains\PhpStorm\ArrayShape;
 use ZxcvbnPhp\Matcher;
 use ZxcvbnPhp\Math\Binomial;
 
@@ -88,10 +87,8 @@ public function __construct(string $password, int $begin, int $end, string $toke
     }
 
     /**
-     * @param bool $isSoleMatch
-     * @return array
+     * @return array{'warning': string, "suggestions": string[]}
      */
-    #[ArrayShape(['warning' => 'string', 'suggestions' => 'string[]'])]
     public function getFeedback(bool $isSoleMatch): array
     {
         $startUpper = '/^[A-Z][^A-Z]+$/u';
diff --git a/src/Matchers/L33tMatch.php b/src/Matchers/L33tMatch.php
index 6b6288b..9163706 100644
--- a/src/Matchers/L33tMatch.php
+++ b/src/Matchers/L33tMatch.php
@@ -4,7 +4,6 @@
 
 namespace ZxcvbnPhp\Matchers;
 
-use JetBrains\PhpStorm\ArrayShape;
 use ZxcvbnPhp\Matcher;
 use ZxcvbnPhp\Math\Binomial;
 
@@ -98,7 +97,9 @@ public function __construct(string $password, int $begin, int $end, string $toke
         }
     }
 
-    #[ArrayShape(['warning' => 'string', 'suggestions' => 'string[]'])]
+    /**
+     * @return array{'warning': string, "suggestions": string[]}
+     */
     public function getFeedback(bool $isSoleMatch): array
     {
         $feedback = parent::getFeedback($isSoleMatch);
diff --git a/src/Matchers/RepeatMatch.php b/src/Matchers/RepeatMatch.php
index 3f38da2..fe44a03 100644
--- a/src/Matchers/RepeatMatch.php
+++ b/src/Matchers/RepeatMatch.php
@@ -4,11 +4,10 @@
 
 namespace ZxcvbnPhp\Matchers;
 
-use JetBrains\PhpStorm\ArrayShape;
 use ZxcvbnPhp\Matcher;
 use ZxcvbnPhp\Scorer;
 
-class RepeatMatch extends BaseMatch
+final class RepeatMatch extends BaseMatch
 {
     public const GREEDY_MATCH = '/(.+)\1+/u';
     public const LAZY_MATCH = '/(.+?)\1+/u';
@@ -85,7 +84,9 @@ public static function match(string $password, array $userInputs = []): array
         return $matches;
     }
 
-    #[ArrayShape(['warning' => 'string', 'suggestions' => 'string[]'])]
+    /**
+     * @return array{'warning': string, "suggestions": string[]}
+     */
     public function getFeedback(bool $isSoleMatch): array
     {
         $warning = mb_strlen($this->repeatedChar) == 1
diff --git a/src/Matchers/ReverseDictionaryMatch.php b/src/Matchers/ReverseDictionaryMatch.php
index c7b86b6..a935bff 100644
--- a/src/Matchers/ReverseDictionaryMatch.php
+++ b/src/Matchers/ReverseDictionaryMatch.php
@@ -4,7 +4,6 @@
 
 namespace ZxcvbnPhp\Matchers;
 
-use JetBrains\PhpStorm\ArrayShape;
 use ZxcvbnPhp\Matcher;
 
 class ReverseDictionaryMatch extends DictionaryMatch
@@ -42,7 +41,9 @@ protected function getRawGuesses(): float
         return parent::getRawGuesses() * 2;
     }
 
-    #[ArrayShape(['warning' => 'string', 'suggestions' => 'string[]'])]
+    /**
+     * @return array{'warning': string, "suggestions": string[]}
+     */
     public function getFeedback(bool $isSoleMatch): array
     {
         $feedback = parent::getFeedback($isSoleMatch);
@@ -54,7 +55,7 @@ public function getFeedback(bool $isSoleMatch): array
         return $feedback;
     }
 
-    public static function mbStrRev(string $string, string $encoding = null): string
+    public static function mbStrRev(string $string, ?string $encoding = null): string
     {
         if ($encoding === null) {
             $encoding = mb_detect_encoding($string) ?: 'UTF-8';
diff --git a/src/Matchers/SequenceMatch.php b/src/Matchers/SequenceMatch.php
index 1350f2a..59531cf 100644
--- a/src/Matchers/SequenceMatch.php
+++ b/src/Matchers/SequenceMatch.php
@@ -4,9 +4,7 @@
 
 namespace ZxcvbnPhp\Matchers;
 
-use JetBrains\PhpStorm\ArrayShape;
-
-class SequenceMatch extends BaseMatch
+final class SequenceMatch extends BaseMatch
 {
     public const MAX_DELTA = 5;
 
@@ -87,7 +85,9 @@ public static function findSequenceMatch(string $password, int $begin, int $end,
         }
     }
 
-    #[ArrayShape(['warning' => 'string', 'suggestions' => 'string[]'])]
+    /**
+     * @return array{'warning': string, "suggestions": string[]}
+     */
     public function getFeedback(bool $isSoleMatch): array
     {
         return [
diff --git a/src/Matchers/SpatialMatch.php b/src/Matchers/SpatialMatch.php
index 6de328b..32297e6 100644
--- a/src/Matchers/SpatialMatch.php
+++ b/src/Matchers/SpatialMatch.php
@@ -4,11 +4,10 @@
 
 namespace ZxcvbnPhp\Matchers;
 
-use JetBrains\PhpStorm\ArrayShape;
 use ZxcvbnPhp\Matcher;
 use ZxcvbnPhp\Math\Binomial;
 
-class SpatialMatch extends BaseMatch
+final class SpatialMatch extends BaseMatch
 {
     public const SHIFTED_CHARACTERS = '~!@#$%^&*()_+QWERTYUIOP{}|ASDFGHJKL:"ZXCVBNM<>?';
 
@@ -58,7 +57,9 @@ public static function match(string $password, array $userInputs = [], array $gr
         return $matches;
     }
 
-    #[ArrayShape(['warning' => 'string', 'suggestions' => 'string[]'])]
+    /**
+     * @return array{'warning': string, "suggestions": string[]}
+     */
     public function getFeedback(bool $isSoleMatch): array
     {
         $warning = $this->turns == 1
@@ -93,7 +94,7 @@ public function __construct(string $password, int $begin, int $end, string $toke
     /**
      * Match spatial patterns in a adjacency graph.
      * @param string $password
-     * @param array  $graph
+     * @param array $graph
      * @param string $graphName
      * @return array
      */
diff --git a/src/Matchers/YearMatch.php b/src/Matchers/YearMatch.php
index 9deeea6..ebabf6b 100644
--- a/src/Matchers/YearMatch.php
+++ b/src/Matchers/YearMatch.php
@@ -4,10 +4,9 @@
 
 namespace ZxcvbnPhp\Matchers;
 
-use JetBrains\PhpStorm\ArrayShape;
 use ZxcvbnPhp\Matcher;
 
-class YearMatch extends BaseMatch
+final class YearMatch extends BaseMatch
 {
     public const NUM_YEARS = 119;
 
@@ -32,7 +31,10 @@ public static function match(string $password, array $userInputs = []): array
         return $matches;
     }
 
-    #[ArrayShape(['warning' => 'string', 'suggestions' => 'string[]'])]
+
+    /**
+     * @return array{'warning': string, "suggestions": string[]}
+     */
     public function getFeedback(bool $isSoleMatch): array
     {
         return [
diff --git a/test/Matchers/MatchTest.php b/test/Matchers/MatchTest.php
deleted file mode 100644
index f5843eb..0000000
--- a/test/Matchers/MatchTest.php
+++ /dev/null
@@ -1,51 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace ZxcvbnPhp\Test\Matchers;
-
-use PHPUnit\Framework\MockObject\MockObject;
-use PHPUnit\Framework\TestCase;
-use ZxcvbnPhp\Matchers\DateMatch;
-
-class MatchTest extends TestCase
-{
-    /**
-     * @param float $guesses
-     * @return MockObject|DateMatch
-     */
-    private function getMatchMock(float $guesses)
-    {
-        $stub = $this->getMockBuilder(DateMatch::class)
-            ->disableOriginalConstructor()
-            ->onlyMethods(['getGuesses'])
-            ->getMock();
-        $stub->method('getGuesses')->willReturn($guesses);
-
-        return $stub;
-    }
-
-    /**
-     * @return float[][]
-     */
-    public function log10Provider(): array
-    {
-        return [
-            [1.0, 0.0],
-            [10.0, 1.0],
-            [100.0, 2.0],
-            [500.0, log10(500)],
-        ];
-    }
-
-    /**
-     * @dataProvider log10Provider
-     * @param float $n
-     * @param float $expected
-     */
-    public function testGuessesLog10(float $n, float $expected): void
-    {
-        $stub = $this->getMatchMock($n);
-        $this->assertSame($expected, $stub->getGuessesLog10(), "log10 guesses");
-    }
-}
diff --git a/test/Matchers/MockMatch.php b/test/Matchers/MockMatch.php
index cf5d10b..869b7e6 100644
--- a/test/Matchers/MockMatch.php
+++ b/test/Matchers/MockMatch.php
@@ -4,7 +4,6 @@
 
 namespace ZxcvbnPhp\Test\Matchers;
 
-use JetBrains\PhpStorm\ArrayShape;
 use ZxcvbnPhp\Matchers\BaseMatch;
 
 class MockMatch extends BaseMatch
@@ -22,10 +21,8 @@ public function __construct(int $begin, int $end, float $guesses)
      * Get feedback to a user based on the match.
      * @param  bool $isSoleMatch
      *   Whether this is the only match in the password
-     * @return array
-     *   Associative array with warning (string) and suggestions (array of strings)
+     * @return array{'warning': string, "suggestions": string[]}
      */
-    #[ArrayShape(['warning' => 'string', 'suggestions' => 'string[]'])]
     public function getFeedback(bool $isSoleMatch): array
     {
         return [
diff --git a/test/ZxcvbnTest.php b/test/ZxcvbnTest.php
index 962ed49..4aab198 100644
--- a/test/ZxcvbnTest.php
+++ b/test/ZxcvbnTest.php
@@ -80,7 +80,7 @@ public function sanityCheckDataProvider()
             ['fortitude22', 2, ['dictionary', 'repeat',], '2 minutes', 1140700],
             ['absoluteadnap', 2, ['dictionary', 'dictionary',], '25 minutes', 15187504],
             ['knifeandspoon', 3, ['dictionary', 'dictionary', 'dictionary'], '1 day', 1108057600],
-            ['h1dden_26191', 3, ['dictionary', 'bruteforce', 'date'], '3 days', 2730628000],
+            ['h1dden_26191', 3, ['dictionary', 'bruteforce', 'date'], '3 days', 2993690800],
             ['4rfv1236yhn!', 4, ['spatial', 'sequence', 'bruteforce'], '1 month', 38980000000],
             ['BVidSNqe3oXVyE1996', 4, ['bruteforce', 'regex',], 'centuries', 10000000000010000],
         ];