diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 8b1f1a0..86e2f14 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -20,7 +20,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.7, 3.8, 3.9, '3.10']
+        python-version: [3.8, 3.9, '3.10']
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python ${{ matrix.python-version }}
diff --git a/facturapi/resources/base.py b/facturapi/resources/base.py
index bf14814..c8ba8b5 100644
--- a/facturapi/resources/base.py
+++ b/facturapi/resources/base.py
@@ -41,8 +41,12 @@ def __init__(self, **_):  # pragma: no cover
 
     @classmethod
     def _from_dict(cls, obj_dict: Dict[str, Any]) -> 'Resource':
-        cls._filter_excess_fields(obj_dict)
-        return cls(**obj_dict)
+        try:
+            cls._filter_excess_fields(obj_dict)
+            return cls(**obj_dict)
+        except Exception as e:
+            print(obj_dict)
+            raise e
 
     @classmethod
     def _filter_excess_fields(cls, obj_dict: Dict[str, Any]) -> None:
diff --git a/facturapi/resources/invoices.py b/facturapi/resources/invoices.py
index f922d35..72af57f 100644
--- a/facturapi/resources/invoices.py
+++ b/facturapi/resources/invoices.py
@@ -17,6 +17,7 @@ class to create the resource and a class to represent an
     ItemPart,
     Namespace,
     ProductBasicInfo,
+    RelatedDocument,
 )
 from ..types.queries import InvoiceQuery
 from .base import Creatable, Deletable, Downloadable, Queryable, Retrievable
@@ -101,11 +102,11 @@ class InvoiceRequest(BaseModel):
     exchange: Optional[float] = 1.0
     conditions: Optional[str]
     foreign_trade: Optional[Dict]
-    related: Optional[List[str]]
-    relation: Optional[InvoiceRelation]
+    related_documents: Optional[List[RelatedDocument]]
     pdf_custom_section: Optional[str]
     addenda: Optional[str]
     namespaces: Optional[Namespace]
+    global_: Optional[Dict] = None
 
 
 @dataclass
@@ -161,6 +162,7 @@ class Invoice(Creatable, Deletable, Downloadable, Queryable, Retrievable):
     series: Optional[str] = None
     related: Optional[List[str]] = None
     relation: Optional[InvoiceRelation] = None
+    global_: Optional[Dict] = None
 
     @classmethod
     def create(cls, data: InvoiceRequest) -> 'Invoice':
@@ -174,10 +176,15 @@ def create(cls, data: InvoiceRequest) -> 'Invoice':
 
         """
         cleaned_data = data.dict(exclude_unset=True, exclude_none=True)
+        if data.global_:
+            cleaned_data['global'] = cleaned_data.pop('global_')
+
         return cast('Invoice', cls._create(**cleaned_data))
 
     @classmethod
-    def cancel(cls, invoice_id: str, motive: str) -> 'Invoice':
+    def cancel(
+        cls, invoice_id: str, motive: str, substitution: Optional[str] = None
+    ) -> 'Invoice':
         """Cancel an invoice.
 
         Calls a DELETE request on invoice resource.
@@ -189,7 +196,10 @@ def cancel(cls, invoice_id: str, motive: str) -> 'Invoice':
             Invoice: The cancelled invoice resource.
 
         """
-        return cast('Invoice', cls._delete(invoice_id, **dict(motive=motive)))
+        data = dict(motive=motive)
+        if substitution:
+            data['substitution'] = substitution
+        return cast('Invoice', cls._delete(invoice_id, **data))
 
     @property
     def customer(self) -> Customer:
diff --git a/facturapi/types/general.py b/facturapi/types/general.py
index 913db82..9e6b7fc 100644
--- a/facturapi/types/general.py
+++ b/facturapi/types/general.py
@@ -2,6 +2,7 @@
 
 from pydantic import BaseModel
 
+from ..types.enums import InvoiceRelation
 from .validators import sanitize_dict
 
 
@@ -71,3 +72,8 @@ class SanitizedDict(dict):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         sanitize_dict(self)
+
+
+class RelatedDocument(BaseModel):
+    relationship: InvoiceRelation
+    documents: List[str] = []
diff --git a/facturapi/types/queries.py b/facturapi/types/queries.py
index 9902fe4..d26f768 100644
--- a/facturapi/types/queries.py
+++ b/facturapi/types/queries.py
@@ -75,3 +75,4 @@ def dict(self, *args, **kwargs) -> Dict[str, Any]:
 
 class InvoiceQuery(BaseQuery):
     motive: Optional[str]
+    substitution: Optional[str]
diff --git a/facturapi/version.py b/facturapi/version.py
index a8ade31..9cb01cb 100644
--- a/facturapi/version.py
+++ b/facturapi/version.py
@@ -1,2 +1,2 @@
-__version__ = '0.1.1'  # pragma: no cover
+__version__ = '0.1.2.dev4'  # pragma: no cover
 CLIENT_VERSION = __version__