diff --git a/api/src/Entity/Action.php b/api/src/Entity/Action.php
index a7122de85..a5afd465f 100644
--- a/api/src/Entity/Action.php
+++ b/api/src/Entity/Action.php
@@ -76,13 +76,17 @@ class Action
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, nullable=true)
      */
-    private $reference;
+    private ?string $reference;
 
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, options={"default": "0.0.0"})
      */
     private string $version = '0.0.0';
diff --git a/api/src/Entity/Application.php b/api/src/Entity/Application.php
index 0698bd2ba..9f47a5d40 100644
--- a/api/src/Entity/Application.php
+++ b/api/src/Entity/Application.php
@@ -104,6 +104,8 @@ class Application
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, nullable=true, options={"default": null})
      */
     private ?string $reference = null;
@@ -111,6 +113,8 @@ class Application
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, options={"default": "0.0.0"})
      */
     private string $version = '0.0.0';
diff --git a/api/src/Entity/CollectionEntity.php b/api/src/Entity/CollectionEntity.php
index 45aa05f46..add253305 100644
--- a/api/src/Entity/CollectionEntity.php
+++ b/api/src/Entity/CollectionEntity.php
@@ -101,6 +101,8 @@ class CollectionEntity
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, nullable=true, options={"default": null})
      */
     private ?string $reference = null;
@@ -108,6 +110,8 @@ class CollectionEntity
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, options={"default": "0.0.0"})
      */
     private string $version = '0.0.0';
diff --git a/api/src/Entity/Cronjob.php b/api/src/Entity/Cronjob.php
index 97c2899b6..c1fce81ff 100644
--- a/api/src/Entity/Cronjob.php
+++ b/api/src/Entity/Cronjob.php
@@ -97,6 +97,8 @@ class Cronjob
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, nullable=true, options={"default": null})
      */
     private ?string $reference = null;
@@ -104,6 +106,8 @@ class Cronjob
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, options={"default": "0.0.0"})
      */
     private string $version = '0.0.0';
diff --git a/api/src/Entity/Endpoint.php b/api/src/Entity/Endpoint.php
index 898226eb1..a125fd3a3 100644
--- a/api/src/Entity/Endpoint.php
+++ b/api/src/Entity/Endpoint.php
@@ -324,6 +324,8 @@ class Endpoint
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, nullable=true)
      */
     private ?string $reference = null;
@@ -331,6 +333,8 @@ class Endpoint
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, options={"default": "0.0.0"})
      */
     private string $version = '0.0.0';
diff --git a/api/src/Entity/Entity.php b/api/src/Entity/Entity.php
index eeabc188e..12b470e79 100644
--- a/api/src/Entity/Entity.php
+++ b/api/src/Entity/Entity.php
@@ -414,6 +414,8 @@ class Entity
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, nullable=true, options={"default": null})
      */
     private ?string $reference = null;
@@ -421,6 +423,8 @@ class Entity
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, options={"default": "0.0.0"})
      */
     private string $version = '0.0.0';
diff --git a/api/src/Entity/Gateway.php b/api/src/Entity/Gateway.php
index 162a8389c..a4467a61f 100644
--- a/api/src/Entity/Gateway.php
+++ b/api/src/Entity/Gateway.php
@@ -217,6 +217,8 @@ class Gateway
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, nullable=true, options={"default": null})
      */
     private ?string $reference = null;
@@ -224,6 +226,8 @@ class Gateway
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, options={"default": "0.0.0"})
      */
     private string $version = '0.0.0';
diff --git a/api/src/Entity/Mapping.php b/api/src/Entity/Mapping.php
index bfd9412f1..98cd88254 100644
--- a/api/src/Entity/Mapping.php
+++ b/api/src/Entity/Mapping.php
@@ -72,6 +72,8 @@ class Mapping
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, nullable=true, options={"default": null})
      */
     private ?string $reference = null;
@@ -79,6 +81,8 @@ class Mapping
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, options={"default": "0.0.0"})
      */
     private string $version = '0.0.0';
diff --git a/api/src/Entity/Organization.php b/api/src/Entity/Organization.php
index 2d35d240b..3483a3ef4 100644
--- a/api/src/Entity/Organization.php
+++ b/api/src/Entity/Organization.php
@@ -103,6 +103,8 @@ class Organization
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, nullable=true, options={"default": null})
      */
     private ?string $reference = null;
@@ -110,6 +112,8 @@ class Organization
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, options={"default": "0.0.0"})
      */
     private string $version = '0.0.0';
diff --git a/api/src/Entity/SecurityGroup.php b/api/src/Entity/SecurityGroup.php
index 86d573b01..4d0e72249 100644
--- a/api/src/Entity/SecurityGroup.php
+++ b/api/src/Entity/SecurityGroup.php
@@ -104,6 +104,8 @@ class SecurityGroup
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, nullable=true, options={"default": null})
      */
     private ?string $reference = null;
@@ -111,6 +113,8 @@ class SecurityGroup
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, options={"default": "0.0.0"})
      */
     private string $version = '0.0.0';
diff --git a/api/src/Entity/Template.php b/api/src/Entity/Template.php
index cbb6d9029..c50bd2c35 100644
--- a/api/src/Entity/Template.php
+++ b/api/src/Entity/Template.php
@@ -131,6 +131,8 @@ class Template
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, nullable=true)
      */
     private ?string $reference = null;
@@ -138,6 +140,8 @@ class Template
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, options={"default": "0.0.0"})
      */
     private string $version = '0.0.0';
diff --git a/api/src/Entity/User.php b/api/src/Entity/User.php
index 9b3a1aa2d..c576217e1 100644
--- a/api/src/Entity/User.php
+++ b/api/src/Entity/User.php
@@ -105,6 +105,8 @@ class User implements PasswordAuthenticatedUserInterface
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, nullable=true, options={"default": null})
      */
     private ?string $reference = null;
@@ -112,6 +114,8 @@ class User implements PasswordAuthenticatedUserInterface
     /**
      * @Groups({"read", "write"})
      *
+     * @Assert\NotNull
+     *
      * @ORM\Column(type="string", length=255, options={"default": "0.0.0"})
      */
     private string $version = '0.0.0';