diff --git a/libagent/device/trezor_defs.py b/libagent/device/trezor_defs.py
index e3d337a..cd59367 100644
--- a/libagent/device/trezor_defs.py
+++ b/libagent/device/trezor_defs.py
@@ -8,78 +8,17 @@ import mnemonic
 import semver
 import trezorlib
 
+from trezorlib.client import TrezorClient as Client
+from trezorlib.exceptions import TrezorFailure, PinException
+from trezorlib.transport import get_transport
+from trezorlib.messages import IdentityType
+
+from trezorlib.btc import get_public_node
+from trezorlib.misc import sign_identity, get_ecdh_session_key
+
 log = logging.getLogger(__name__)
 
 
-if semver.match(trezorlib.__version__, ">=0.11.0"):
-    from trezorlib.client import TrezorClient as Client
-    from trezorlib.exceptions import TrezorFailure, PinException
-    from trezorlib.transport import get_transport
-    from trezorlib.messages import IdentityType
-
-    from trezorlib.btc import get_public_node
-    from trezorlib.misc import sign_identity, get_ecdh_session_key
-
-else:
-    from trezorlib.client import (TrezorClient, PinException,
-                                  CallException as TrezorFailure)
-    from trezorlib.messages import IdentityType
-    from trezorlib import messages
-    from trezorlib.transport import get_transport
-
-    get_public_node = TrezorClient.get_public_node
-    sign_identity = TrezorClient.sign_identity
-    get_ecdh_session_key = TrezorClient.get_ecdh_session_key
-
-    class Client(TrezorClient):
-        """Compatibility wrapper for older TrezorClient type.
-
-        This class redirects callback_* style methods to the UI implementation,
-        and stores state so that we can reuse it.
-        """
-
-        def __init__(self, transport, ui, state=None):
-            """C-tor."""
-            super().__init__(transport, state=state)
-            self.ui = ui
-
-        def callback_PinMatrixRequest(self, msg):
-            """Redirect PinMatrixRequest to UI."""
-            try:
-                pin = self.ui.get_pin(msg.type)
-                if not pin.isdigit():
-                    raise PinException(
-                        None, 'Invalid scrambled PIN: {!r}'.format(pin))
-                return messages.PinMatrixAck(pin=pin)
-            except:  # noqa
-                self.init_device()
-                raise
-
-        def callback_PassphraseRequest(self, msg):
-            """Redirect PassphraseRequest to UI."""
-            try:
-                if msg.on_device is True:
-                    return messages.PassphraseAck()
-
-                passphrase = self.ui.get_passphrase()
-                passphrase = mnemonic.Mnemonic.normalize_string(passphrase)
-
-                length = len(passphrase)
-                if length > 50:
-                    msg = 'Too long passphrase ({} chars)'.format(length)
-                    raise ValueError(msg)
-
-                return messages.PassphraseAck(passphrase=passphrase)
-            except:  # noqa
-                self.init_device()
-                raise
-
-        def callback_PassphraseStateRequest(self, msg):
-            """Store state provided by device so that we can reuse it later."""
-            self.state = msg.state  # pylint: disable=attribute-defined-outside-init
-            return messages.PassphraseStateAck()
-
-
 def find_device():
     """Selects a transport based on `TREZOR_PATH` environment variable.