diff --git a/ereuse_devicehub/migrations/versions/378b6b147b46_nullable.py b/ereuse_devicehub/migrations/versions/378b6b147b46_nullable.py
index 1a8e06c9..670749f7 100644
--- a/ereuse_devicehub/migrations/versions/378b6b147b46_nullable.py
+++ b/ereuse_devicehub/migrations/versions/378b6b147b46_nullable.py
@@ -28,6 +28,9 @@ def get_inv():
 
 def upgrade():
     op.alter_column('computer', 'chassis', nullable=True, schema=f'{get_inv()}')
+    op.alter_column('display', 'size', nullable=True, schema=f'{get_inv()}')
+    op.alter_column('display', 'resolution_width', nullable=True, schema=f'{get_inv()}')
+    op.alter_column('display', 'resolution_height', nullable=True, schema=f'{get_inv()}')
     # pass
 
 
diff --git a/ereuse_devicehub/resources/action/schemas.py b/ereuse_devicehub/resources/action/schemas.py
index 4d07d405..b29aa06a 100644
--- a/ereuse_devicehub/resources/action/schemas.py
+++ b/ereuse_devicehub/resources/action/schemas.py
@@ -260,9 +260,8 @@ class TestBios(Test):
 
 class VisualTest(Test):
     __doc__ = m.VisualTest.__doc__
-    appearance_range = EnumField(AppearanceRange, required=True, data_key='appearanceRange')
+    appearance_range = EnumField(AppearanceRange, data_key='appearanceRange')
     functionality_range = EnumField(FunctionalityRange,
-                                    required=True,
                                     data_key='functionalityRange')
     labelling = Boolean()
 
diff --git a/ereuse_devicehub/resources/device/models.py b/ereuse_devicehub/resources/device/models.py
index fd75858b..f929ff1f 100644
--- a/ereuse_devicehub/resources/device/models.py
+++ b/ereuse_devicehub/resources/device/models.py
@@ -342,19 +342,19 @@ class Device(Thing):
 
 class DisplayMixin:
     """Base class for the Display Component and the Monitor Device."""
-    size = Column(Float(decimal_return_scale=1), check_range('size', 2, 150), nullable=False)
+    size = Column(Float(decimal_return_scale=1), check_range('size', 2, 150), nullable=True)
     size.comment = """The size of the monitor in inches."""
     technology = Column(DBEnum(DisplayTech))
     technology.comment = """The technology the monitor uses to display
     the image.
     """
     resolution_width = Column(SmallInteger, check_range('resolution_width', 10, 20000),
-                              nullable=False)
+                              nullable=True)
     resolution_width.comment = """The maximum horizontal resolution the
     monitor can natively support in pixels.
     """
     resolution_height = Column(SmallInteger, check_range('resolution_height', 10, 20000),
-                               nullable=False)
+                               nullable=True)
     resolution_height.comment = """The maximum vertical resolution the
     monitor can natively support in pixels.
     """