diff --git a/src/Entity/Attachment.php b/src/Entity/Attachment.php
index ff53e707..7cbe253e 100644
--- a/src/Entity/Attachment.php
+++ b/src/Entity/Attachment.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  *
  * Part-DB Version 0.4+ "nextgen"
diff --git a/src/Entity/AttachmentContainingDBElement.php b/src/Entity/AttachmentContainingDBElement.php
index 59faa071..77233c84 100644
--- a/src/Entity/AttachmentContainingDBElement.php
+++ b/src/Entity/AttachmentContainingDBElement.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  *
  * Part-DB Version 0.4+ "nextgen"
diff --git a/src/Entity/AttachmentType.php b/src/Entity/AttachmentType.php
index 5f317e60..1283a1bc 100644
--- a/src/Entity/AttachmentType.php
+++ b/src/Entity/AttachmentType.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  *
  * Part-DB Version 0.4+ "nextgen"
diff --git a/src/Entity/Category.php b/src/Entity/Category.php
index 858b2ef5..9c7e37eb 100644
--- a/src/Entity/Category.php
+++ b/src/Entity/Category.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  *
  * Part-DB Version 0.4+ "nextgen"
diff --git a/src/Entity/Company.php b/src/Entity/Company.php
index 8b2faa30..da64b289 100644
--- a/src/Entity/Company.php
+++ b/src/Entity/Company.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  *
  * Part-DB Version 0.4+ "nextgen"
diff --git a/src/Entity/DBElement.php b/src/Entity/DBElement.php
index 37815dd4..905584e9 100644
--- a/src/Entity/DBElement.php
+++ b/src/Entity/DBElement.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  *
  * Part-DB Version 0.4+ "nextgen"
diff --git a/src/Entity/DevicePart.php b/src/Entity/DevicePart.php
index 931d7c74..09b57cb7 100644
--- a/src/Entity/DevicePart.php
+++ b/src/Entity/DevicePart.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 /**
  *
diff --git a/src/Entity/Footprint.php b/src/Entity/Footprint.php
index 0c45676e..9edfe507 100644
--- a/src/Entity/Footprint.php
+++ b/src/Entity/Footprint.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 /**
  *
diff --git a/src/Entity/Manufacturer.php b/src/Entity/Manufacturer.php
index 8d9b0c1a..f834fc1e 100644
--- a/src/Entity/Manufacturer.php
+++ b/src/Entity/Manufacturer.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 /**
  *
diff --git a/src/Entity/NamedDBElement.php b/src/Entity/NamedDBElement.php
index 3c2c4609..926b8917 100644
--- a/src/Entity/NamedDBElement.php
+++ b/src/Entity/NamedDBElement.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  *
  * Part-DB Version 0.4+ "nextgen"
diff --git a/src/Entity/Orderdetail.php b/src/Entity/Orderdetail.php
index 1a79c7f8..d5113389 100644
--- a/src/Entity/Orderdetail.php
+++ b/src/Entity/Orderdetail.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 /**
  *
diff --git a/src/Entity/Part.php b/src/Entity/Part.php
index 18f2a8e3..d84c8fd2 100644
--- a/src/Entity/Part.php
+++ b/src/Entity/Part.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 /**
  *
diff --git a/src/Entity/PartsContainingDBElement.php b/src/Entity/PartsContainingDBElement.php
index 14f74845..215957b1 100644
--- a/src/Entity/PartsContainingDBElement.php
+++ b/src/Entity/PartsContainingDBElement.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  *
  * Part-DB Version 0.4+ "nextgen"
diff --git a/src/Entity/Pricedetail.php b/src/Entity/Pricedetail.php
index 277ef00e..0de0a8f4 100644
--- a/src/Entity/Pricedetail.php
+++ b/src/Entity/Pricedetail.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 /**
  *
diff --git a/src/Entity/Storelocation.php b/src/Entity/Storelocation.php
index a8679714..1f6928d6 100644
--- a/src/Entity/Storelocation.php
+++ b/src/Entity/Storelocation.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 
 /**
diff --git a/src/Entity/StructuralDBElement.php b/src/Entity/StructuralDBElement.php
index 3f5cf35c..f3753a77 100644
--- a/src/Entity/StructuralDBElement.php
+++ b/src/Entity/StructuralDBElement.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 /**
  *
  * Part-DB Version 0.4+ "nextgen"
diff --git a/src/Entity/Supplier.php b/src/Entity/Supplier.php
index 4f71f8d4..5f484cc1 100644
--- a/src/Entity/Supplier.php
+++ b/src/Entity/Supplier.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 /**
  *