diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index de1cedfc..20a49bf3 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -24,7 +24,7 @@ jobs:
 
         strategy:
             matrix:
-                php-version: [ '7.4', '8.0' ]
+                php-version: [ '7.4', '8.0', '8.1' ]
 
         steps:
             - name: Checkout
@@ -58,7 +58,7 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                php-version: [ '7.1', '7.2', '7.3', '7.4', '8.0' ]
+                php-version: [ '7.1', '7.2', '7.3', '7.4', '8.0', '8.1' ]
                 deps: [ 'lowest', 'newest' ]
                 exclude:
                     - php-version: '7.2'
@@ -69,6 +69,8 @@ jobs:
                       deps: lowest
                     - php-version: '8.0'
                       deps: lowest
+                    - php-version: '8.1'
+                      deps: lowest
 
         runs-on: ubuntu-latest
 
diff --git a/composer.json b/composer.json
index 2f80da3a..f78f2710 100644
--- a/composer.json
+++ b/composer.json
@@ -25,7 +25,7 @@
 		"nette/caching": "~2.5 || ~3.0",
 		"nette/utils": "~2.5 || ~3.0",
 		"nette/tokenizer": "~2.3 || ~3.0",
-		"nextras/dbal": "~4.0"
+		"nextras/dbal": "~4.0@dev"
 	},
 	"require-dev": {
 		"nette/bootstrap": "~2.4 || ~3.0",
diff --git a/src/Collection/EntityIterator.php b/src/Collection/EntityIterator.php
index 06a5e40a..4e60291c 100644
--- a/src/Collection/EntityIterator.php
+++ b/src/Collection/EntityIterator.php
@@ -63,6 +63,7 @@ public function current(): IEntity
 	}
 
 
+	#[\ReturnTypeWillChange]
 	public function key()
 	{
 		return $this->position;
diff --git a/src/Collection/MultiEntityIterator.php b/src/Collection/MultiEntityIterator.php
index 794e76fa..d3311e93 100644
--- a/src/Collection/MultiEntityIterator.php
+++ b/src/Collection/MultiEntityIterator.php
@@ -81,6 +81,7 @@ public function current(): IEntity
 	}
 
 
+	#[\ReturnTypeWillChange]
 	public function key()
 	{
 		return $this->position;
diff --git a/src/Entity/Reflection/PropertyMetadata.php b/src/Entity/Reflection/PropertyMetadata.php
index 6fd9cf2c..bbb7f364 100644
--- a/src/Entity/Reflection/PropertyMetadata.php
+++ b/src/Entity/Reflection/PropertyMetadata.php
@@ -189,7 +189,7 @@ public function isValid(&$value): bool
 					$value = $tmp->setTimezone(new DateTimeZone(date_default_timezone_get()));
 					return true;
 
-				} elseif (ctype_digit($value)) {
+				} elseif (ctype_digit((string) $value)) {
 					$value = new $rawType("@{$value}");
 					return true;
 				}