diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 5bb976da2c4deccf986784eddc900b21fce2cab9..fa1254d02cff828bef85366164bc3cd34b2c0795 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -10,18 +10,18 @@ repos:
     - id: isort
       args: ["--profile", "black"]
 -   repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v0.982
+    rev: v0.991
     hooks:
     - id: mypy
       args:
         - "--install-types"
         - "--non-interactive"
 -   repo: https://github.com/PyCQA/pylint
-    rev: v2.15.4
+    rev: v2.15.8
     hooks:
     - id: pylint
 -   repo: https://github.com/asottile/pyupgrade
-    rev: v3.1.0
+    rev: v3.3.1
     hooks:
     - id: pyupgrade
       args: [--py37-plus]
diff --git a/duniterpy/api/bma/blockchain.py b/duniterpy/api/bma/blockchain.py
index 1849bd0420f9411aae8d1bc6db9b4a50e28dcc64..8110cc67c2495853aec331154fb95449993d9fd9 100644
--- a/duniterpy/api/bma/blockchain.py
+++ b/duniterpy/api/bma/blockchain.py
@@ -15,7 +15,7 @@
 
 import logging
 from http.client import HTTPResponse
-from typing import Union
+from typing import Optional, Union
 
 from duniterpy.api.client import RESPONSE_HTTP, Client
 
@@ -266,7 +266,10 @@ def current(client: Client) -> dict:
 
 
 def block(
-    client: Client, number: int = 0, block_raw: str = None, signature: str = None
+    client: Client,
+    number: int = 0,
+    block_raw: Optional[str] = None,
+    signature: Optional[str] = None,
 ) -> Union[dict, HTTPResponse]:
     """
     GET/POST a block from/to the blockchain
diff --git a/duniterpy/api/endpoint.py b/duniterpy/api/endpoint.py
index 89596fdaabffd32e5771aa7bdcc87774a84d55c7..829c44222268482ae3a2f9571661c22da4375117 100644
--- a/duniterpy/api/endpoint.py
+++ b/duniterpy/api/endpoint.py
@@ -67,7 +67,7 @@ class Endpoint:
     def inline(self) -> str:
         raise NotImplementedError("inline() is not implemented")
 
-    def conn_handler(self, proxy: str = None) -> ConnectionHandler:
+    def conn_handler(self, proxy: Optional[str] = None) -> ConnectionHandler:
         raise NotImplementedError("conn_handler is not implemented")
 
     def __str__(self) -> str:
@@ -114,7 +114,7 @@ class UnknownEndpoint(Endpoint):
             doc += f" {p}"
         return doc
 
-    def conn_handler(self, proxy: str = None) -> ConnectionHandler:
+    def conn_handler(self, proxy: Optional[str] = None) -> ConnectionHandler:
         """
         Return connection handler
 
@@ -188,7 +188,7 @@ class BMAEndpoint(Endpoint):
         ]
         return f'{self.API} {" ".join(inlined)}'
 
-    def conn_handler(self, proxy: str = None) -> ConnectionHandler:
+    def conn_handler(self, proxy: Optional[str] = None) -> ConnectionHandler:
         """
         Return connection handler instance for the endpoint
 
@@ -285,7 +285,7 @@ class SecuredBMAEndpoint(BMAEndpoint):
         ]
         return f'{self.API} {" ".join(inlined)}'
 
-    def conn_handler(self, proxy: str = None) -> ConnectionHandler:
+    def conn_handler(self, proxy: Optional[str] = None) -> ConnectionHandler:
         """
         Return connection handler instance for the endpoint
 
@@ -354,7 +354,7 @@ class WS2PEndpoint(Endpoint):
         ]
         return f'{self.API} {" ".join(inlined)}'
 
-    def conn_handler(self, proxy: str = None) -> ConnectionHandler:
+    def conn_handler(self, proxy: Optional[str] = None) -> ConnectionHandler:
         """
         Return connection handler instance for the endpoint
 
@@ -425,7 +425,7 @@ class ESCoreEndpoint(Endpoint):
         inlined = [str(info) for info in (self.host, self.port) if info]
         return f'{self.API} {" ".join(inlined)}'
 
-    def conn_handler(self, proxy: str = None) -> ConnectionHandler:
+    def conn_handler(self, proxy: Optional[str] = None) -> ConnectionHandler:
         """
         Return connection handler instance for the endpoint
 
@@ -484,7 +484,7 @@ class ESUserEndpoint(Endpoint):
         inlined = [str(info) for info in (self.host, self.port) if info]
         return f'{self.API} {" ".join(inlined)}'
 
-    def conn_handler(self, proxy: str = None) -> ConnectionHandler:
+    def conn_handler(self, proxy: Optional[str] = None) -> ConnectionHandler:
         """
         Return connection handler instance for the endpoint
 
@@ -547,7 +547,7 @@ class ESSubscribtionEndpoint(Endpoint):
         inlined = [str(info) for info in (self.host, self.port) if info]
         return f'{self.API} {" ".join(inlined)}'
 
-    def conn_handler(self, proxy: str = None) -> ConnectionHandler:
+    def conn_handler(self, proxy: Optional[str] = None) -> ConnectionHandler:
         """
         Return connection handler instance for the endpoint
 
@@ -646,7 +646,7 @@ class GVAEndpoint(Endpoint):
         ]
         return f'{self.API} {" ".join(inlined)}'
 
-    def conn_handler(self, proxy: str = None) -> ConnectionHandler:
+    def conn_handler(self, proxy: Optional[str] = None) -> ConnectionHandler:
         """
         Return connection handler instance for the endpoint
 
diff --git a/duniterpy/documents/block.py b/duniterpy/documents/block.py
index a5d4d195d2e5b8d8784a8d4bd3c9a92013bafd72..3580159962dcfd0309effac90340e2d893ebc079 100644
--- a/duniterpy/documents/block.py
+++ b/duniterpy/documents/block.py
@@ -168,7 +168,7 @@ class Block(Document):
         transactions: List[Transaction],
         inner_hash: str,
         nonce: int,
-        signing_key: SigningKey = None,
+        signing_key: Optional[SigningKey] = None,
         version: int = VERSION,
         currency: str = G1_CURRENCY_CODENAME,
     ) -> None:
diff --git a/duniterpy/documents/certification.py b/duniterpy/documents/certification.py
index c268b9a947db89f0939658505e1cfd748e6bf5ad..8aa4fd828640f87987d4545d8909899848248180 100644
--- a/duniterpy/documents/certification.py
+++ b/duniterpy/documents/certification.py
@@ -57,7 +57,7 @@ class Certification(Document):
         pubkey_from: str,
         identity: Union[Identity, str],
         block_id: BlockID,
-        signing_key: SigningKey = None,
+        signing_key: Optional[SigningKey] = None,
         version: int = VERSION,
         currency: str = G1_CURRENCY_CODENAME,
     ) -> None:
diff --git a/duniterpy/documents/identity.py b/duniterpy/documents/identity.py
index dda8f37e53ff15420839f63959c0f44bcbd15131..1437320c44a7618e7d1756ab4f428239242cf2a8 100644
--- a/duniterpy/documents/identity.py
+++ b/duniterpy/documents/identity.py
@@ -14,7 +14,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import re
-from typing import Any, Type, TypeVar
+from typing import Any, Optional, Type, TypeVar
 
 from ..constants import (
     BLOCK_ID_REGEX,
@@ -73,7 +73,7 @@ class Identity(Document):
         pubkey: str,
         uid: str,
         block_id: BlockID,
-        signing_key: SigningKey = None,
+        signing_key: Optional[SigningKey] = None,
         version: int = VERSION,
         currency: str = G1_CURRENCY_CODENAME,
     ) -> None:
diff --git a/duniterpy/documents/membership.py b/duniterpy/documents/membership.py
index 3ce7a407e28c4694359b7160455b08b60b4c045b..4ff7ac996fe6ac6875aa534c4b5bc845417bf6a8 100644
--- a/duniterpy/documents/membership.py
+++ b/duniterpy/documents/membership.py
@@ -14,7 +14,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import re
-from typing import Any, Type, TypeVar
+from typing import Any, Optional, Type, TypeVar
 
 from ..constants import (
     BLOCK_ID_REGEX,
@@ -77,7 +77,7 @@ class Membership(Document):
         membership_block_id: BlockID,
         uid: str,
         identity_block_id: BlockID,
-        signing_key: SigningKey = None,
+        signing_key: Optional[SigningKey] = None,
         version: int = VERSION,
         currency: str = G1_CURRENCY_CODENAME,
         membership_type: str = "IN",
diff --git a/duniterpy/documents/peer.py b/duniterpy/documents/peer.py
index cfe5beece5069f1231b252c87120215632d5a7bf..408549188ebd65acfb119fdae73b036bba17b415 100644
--- a/duniterpy/documents/peer.py
+++ b/duniterpy/documents/peer.py
@@ -14,7 +14,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import re
-from typing import List, Type, TypeVar
+from typing import List, Optional, Type, TypeVar
 
 from duniterpy.api.endpoint import Endpoint, endpoint
 
@@ -67,7 +67,7 @@ class Peer(Document):
         pubkey: str,
         block_id: BlockID,
         endpoints: List[Endpoint],
-        signing_key: SigningKey = None,
+        signing_key: Optional[SigningKey] = None,
         version: int = VERSION,
         currency: str = G1_CURRENCY_CODENAME,
     ) -> None:
diff --git a/duniterpy/documents/revocation.py b/duniterpy/documents/revocation.py
index 528ca2d8e9b0bed63bca8be7f5900b9f7ee9a8b6..b30bfa1b27d5b2cf15cf0e667eda2d0722afdd33 100644
--- a/duniterpy/documents/revocation.py
+++ b/duniterpy/documents/revocation.py
@@ -14,7 +14,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import re
-from typing import Any, Type, TypeVar, Union
+from typing import Any, Optional, Type, TypeVar, Union
 
 from ..constants import (
     BLOCK_ID_REGEX,
@@ -59,7 +59,7 @@ class Revocation(Document):
     def __init__(
         self,
         identity: Union[Identity, str],
-        signing_key: SigningKey = None,
+        signing_key: Optional[SigningKey] = None,
         version: int = VERSION,
         currency: str = G1_CURRENCY_CODENAME,
     ) -> None:
diff --git a/duniterpy/grammars/output.py b/duniterpy/grammars/output.py
index f9e0ef5055be94ce1f91221a18941e9ff941b853..a87d482708554b16bc435a7069055241343ea5b0 100644
--- a/duniterpy/grammars/output.py
+++ b/duniterpy/grammars/output.py
@@ -151,7 +151,7 @@ class CSV:
         return csv
 
     def compose(
-        self, parser: Any = None, grammar: Any = None, attr_of: str = None
+        self, parser: Any = None, grammar: Any = None, attr_of: Optional[str] = None
     ) -> str:
         """
         Return the CSV(time) expression as string format
@@ -210,7 +210,7 @@ class CLTV:
         return cltv
 
     def compose(
-        self, parser: Any = None, grammar: Any = None, attr_of: str = None
+        self, parser: Any = None, grammar: Any = None, attr_of: Optional[str] = None
     ) -> str:
         """
         Return the CLTV(timestamp) expression as string format
@@ -269,7 +269,7 @@ class XHX:
         return xhx
 
     def compose(
-        self, parser: Any = None, grammar: Any = None, attr_of: str = None
+        self, parser: Any = None, grammar: Any = None, attr_of: Optional[str] = None
     ) -> str:
         """
         Return the XHX(sha_hash) expression as string format
@@ -305,7 +305,7 @@ class Operator(Keyword):
         return op
 
     def compose(
-        self, parser: Any = None, grammar: Any = None, attr_of: str = None
+        self, parser: Any = None, grammar: Any = None, attr_of: Optional[str] = None
     ) -> str:
         """
         Return the Operator keyword as string format
@@ -382,7 +382,9 @@ class Condition:
             condition.right = right
         return condition
 
-    def compose(self, parser: Any, grammar: Any = None, attr_of: str = None) -> str:
+    def compose(
+        self, parser: Any, grammar: Any = None, attr_of: Optional[str] = None
+    ) -> str:
         """
         Return the Condition as string format
 
diff --git a/duniterpy/key/signing_key.py b/duniterpy/key/signing_key.py
index 08d08007b1ba41c10ad1978822a8655301d2575c..53e2fe8a454adf7b941a6e03a4916a0aebbbf17b 100644
--- a/duniterpy/key/signing_key.py
+++ b/duniterpy/key/signing_key.py
@@ -500,7 +500,9 @@ Data: {ewif_key}"
 
     @classmethod
     def from_dubp_mnemonic(
-        cls: Type[SigningKeyType], mnemonic: str, scrypt_params: ScryptParams = None
+        cls: Type[SigningKeyType],
+        mnemonic: str,
+        scrypt_params: Optional[ScryptParams] = None,
     ) -> SigningKeyType:
         """
         Generate key pair instance from a DUBP mnemonic passphrase