diff --git a/pySim/cards.py b/pySim/cards.py
index 18e4ef3..55965d7 100644
--- a/pySim/cards.py
+++ b/pySim/cards.py
@@ -52,7 +52,7 @@
     return res
 
 
-class SimCard(object):
+class SimCard:
 
     name = 'SIM'
 
diff --git a/pySim/commands.py b/pySim/commands.py
index 7b50677..fa0458a 100644
--- a/pySim/commands.py
+++ b/pySim/commands.py
@@ -27,7 +27,7 @@
 from pySim.exceptions import SwMatchError
 
 
-class SimCardCommands(object):
+class SimCardCommands:
     def __init__(self, transport):
         self._tp = transport
         self.cla_byte = "a0"
diff --git a/pySim/filesystem.py b/pySim/filesystem.py
index 7c5d49a..37c668d 100644
--- a/pySim/filesystem.py
+++ b/pySim/filesystem.py
@@ -49,7 +49,7 @@
 # tuple: logical-and of the listed services requires this file
 CardFileService = Union[int, List[int], Tuple[int, ...]]
 
-class CardFile(object):
+class CardFile:
     """Base class for all objects in the smart card filesystem.
     Serve as a common ancestor to all other file types; rarely used directly.
     """
@@ -1230,7 +1230,7 @@
         self.shell_commands = [self.ShellCommands()]
 
 
-class RuntimeState(object):
+class RuntimeState:
     """Represent the runtime state of a session with a card."""
 
     def __init__(self, card, profile: 'CardProfile'):
@@ -1648,7 +1648,7 @@
                 cmd_app.unregister_command_set(c)
 
 
-class FileData(object):
+class FileData:
     """Represent the runtime, on-card data."""
 
     def __init__(self, fdesc):
@@ -1676,7 +1676,7 @@
     return None
 
 
-class CardApplication(object):
+class CardApplication:
     """A card application is represented by an ADF (with contained hierarchy) and optionally
        some SW definitions."""
 
diff --git a/pySim/profile.py b/pySim/profile.py
index d5df083..c535bac 100644
--- a/pySim/profile.py
+++ b/pySim/profile.py
@@ -62,7 +62,7 @@
     return _mf_select_test(scc, "a0", "0000")
 
 
-class CardProfile(object):
+class CardProfile:
     """A Card Profile describes a card, it's filesystem hierarchy, an [initial] list of
     applications as well as profile-specific SW and shell commands.  Every card has
     one card profile, but there may be multiple applications within that profile."""
diff --git a/pySim/transport/calypso.py b/pySim/transport/calypso.py
index 15c9e5f..e1326ac 100644
--- a/pySim/transport/calypso.py
+++ b/pySim/transport/calypso.py
@@ -26,7 +26,7 @@
 from pySim.utils import h2b, b2h
 
 
-class L1CTLMessage(object):
+class L1CTLMessage:
 
     # Every (encoded) L1CTL message has the following structure:
     #  - msg_length (2 bytes, net order)