diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3fddc974..acae62be 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,7 +9,7 @@
 - Chg #308: Replace call of `SchemaInterface::getRawTableName()` to `QuoterInterface::getRawTableName()` (@Tigrov)
 - Enh #312: Refactor `bit` type (@Tigrov)
 - Enh #315: Refactor PHP type of `ColumnSchemaInterface` instances (@Tigrov)
-- Chg #317: Raise minimum PHP version to `^8.1` (@Tigrov)
+- Enh #317: Raise minimum PHP version to `^8.1` with minor refactoring (@Tigrov)
 
 ## 1.2.0 March 21, 2024
 
diff --git a/rector.php b/rector.php
index 7e1860ee..1474cb20 100644
--- a/rector.php
+++ b/rector.php
@@ -4,8 +4,8 @@
 
 use Rector\CodeQuality\Rector\Class_\InlineConstructorDefaultToPropertyRector;
 use Rector\Config\RectorConfig;
-use Rector\Php73\Rector\FuncCall\JsonThrowOnErrorRector;
-use Rector\Php74\Rector\Closure\ClosureToArrowFunctionRector;
+use Rector\Php81\Rector\FuncCall\NullToStrictStringFuncCallArgRector;
+use Rector\Php81\Rector\Property\ReadOnlyPropertyRector;
 use Rector\Set\ValueObject\LevelSetList;
 
 return static function (RectorConfig $rectorConfig): void {
@@ -22,11 +22,11 @@
 
     // define sets of rules
     $rectorConfig->sets([
-        LevelSetList::UP_TO_PHP_80,
+        LevelSetList::UP_TO_PHP_81,
     ]);
 
     $rectorConfig->skip([
-        ClosureToArrowFunctionRector::class,
-        JsonThrowOnErrorRector::class,
+        NullToStrictStringFuncCallArgRector::class,
+        ReadOnlyPropertyRector::class,
     ]);
 };
diff --git a/src/DQLQueryBuilder.php b/src/DQLQueryBuilder.php
index 2dbeaa92..b01d5953 100644
--- a/src/DQLQueryBuilder.php
+++ b/src/DQLQueryBuilder.php
@@ -16,7 +16,6 @@
 use Yiisoft\Db\QueryBuilder\Condition\InCondition;
 use Yiisoft\Db\QueryBuilder\Condition\LikeCondition;
 
-use function array_merge;
 use function preg_match;
 
 /**
@@ -47,11 +46,12 @@ public function selectExists(string $rawSql): string
 
     protected function defaultExpressionBuilders(): array
     {
-        return array_merge(parent::defaultExpressionBuilders(), [
+        return [
+            ...parent::defaultExpressionBuilders(),
             InCondition::class => InConditionBuilder::class,
             LikeCondition::class => LikeConditionBuilder::class,
             Expression::class => ExpressionBuilder::class,
-        ]);
+        ];
     }
 
     /**
diff --git a/src/Quoter.php b/src/Quoter.php
index 33d76a24..0d50d1c6 100644
--- a/src/Quoter.php
+++ b/src/Quoter.php
@@ -30,7 +30,7 @@ public function getTableNameParts(string $name, bool $withColumn = false): array
         if (preg_match_all('/([^.\[\]]+)|\[([^\[\]]+)]/', $name, $matches) > 0) {
             $parts = array_slice($matches[0], -4, 4);
 
-            return array_map([$this, 'unquoteSimpleTableName'], $parts);
+            return array_map($this->unquoteSimpleTableName(...), $parts);
         }
 
         return [$this->unquoteSimpleTableName($name)];
diff --git a/src/Schema.php b/src/Schema.php
index 226c7e74..c7cfc9d2 100644
--- a/src/Schema.php
+++ b/src/Schema.php
@@ -19,6 +19,7 @@
 use Yiisoft\Db\Schema\Column\ColumnSchemaInterface;
 use Yiisoft\Db\Schema\TableSchemaInterface;
 
+use function array_change_key_case;
 use function array_map;
 use function explode;
 use function is_array;
@@ -333,7 +334,7 @@ protected function loadTableIndexes(string $tableName): array
         $indexes = $this->db->createCommand($sql, [':fullName' => $resolvedName->getFullName()])->queryAll();
 
         /** @psalm-var array[] $indexes */
-        $indexes = array_map('array_change_key_case', $indexes);
+        $indexes = array_map(array_change_key_case(...), $indexes);
         $indexes = DbArrayHelper::index($indexes, null, ['name']);
 
         $result = [];
@@ -840,7 +841,7 @@ private function loadTableConstraints(string $tableName, string $returnType): mi
         $constraints = $this->db->createCommand($sql, [':fullName' => $resolvedName->getFullName()])->queryAll();
 
         /** @psalm-var array[] $constraints */
-        $constraints = array_map('array_change_key_case', $constraints);
+        $constraints = array_map(array_change_key_case(...), $constraints);
         $constraints = DbArrayHelper::index($constraints, null, ['type', 'name']);
 
         $result = [
@@ -909,12 +910,10 @@ private function loadTableConstraints(string $tableName, string $returnType): mi
      * @param string $name The table name.
      *
      * @return array The cache key.
-     *
-     * @psalm-suppress DeprecatedMethod
      */
     protected function getCacheKey(string $name): array
     {
-        return array_merge([self::class], $this->generateCacheKey(), [$this->db->getQuoter()->getRawTableName($name)]);
+        return [self::class, ...$this->generateCacheKey(), $this->db->getQuoter()->getRawTableName($name)];
     }
 
     /**
@@ -926,7 +925,7 @@ protected function getCacheKey(string $name): array
      */
     protected function getCacheTag(): string
     {
-        return md5(serialize(array_merge([self::class], $this->generateCacheKey())));
+        return md5(serialize([self::class, ...$this->generateCacheKey()]));
     }
 
     private function parseDefaultValue(string $value): string
diff --git a/tests/SchemaTest.php b/tests/SchemaTest.php
index 58d2a9ee..3be139c2 100644
--- a/tests/SchemaTest.php
+++ b/tests/SchemaTest.php
@@ -155,7 +155,8 @@ function ($params) use ($expectedTableName) {
 
     public function withIndexDataProvider(): array
     {
-        return array_merge(parent::withIndexDataProvider(), [
+        return [
+            ...parent::withIndexDataProvider(),
             [
                 'indexType' => SchemaInterface::INDEX_CLUSTERED,
                 'indexMethod' => null,
@@ -166,7 +167,7 @@ public function withIndexDataProvider(): array
                 'indexMethod' => null,
                 'columnType' => 'varchar(16)',
             ],
-        ]);
+        ];
     }
 
     public function testNotConnectionPDO(): void