diff --git a/setup.py b/setup.py
index f8cfa7c17..57a7fe88e 100644
--- a/setup.py
+++ b/setup.py
@@ -2,12 +2,11 @@ import os
 import re
 from setuptools import setup, find_packages
 
-init_file = open(os.path.join(os.path.dirname(__path__), 'torba', '__init__.py')).read()
-version = re.search('\d+\.\d+\.\d+', init_file).group()
+import torba
 
 setup(
     name='torba',
-    version=version,
+    version=torba.__version__,
     url='https://github.com/lbryio/torba',
     license='MIT',
     author='LBRY Inc.',
@@ -29,7 +28,7 @@ setup(
     ),
     packages=find_packages(exclude=('tests',)),
     include_package_data=True,
-    python_requires='>=2.7,>=3.6',
+    python_requires='>=2.7',
     install_requires=(
         'twisted',
         'ecdsa',
diff --git a/tests/unit/test_account.py b/tests/unit/test_account.py
index a01aacbdd..3648c5fe4 100644
--- a/tests/unit/test_account.py
+++ b/tests/unit/test_account.py
@@ -39,25 +39,25 @@ class TestAccount(unittest.TestCase):
         )
         self.assertEqual(
             account.private_key.extended_key_string(),
-            'xprv9s21ZrQH143K2dyhK7SevfRG72bYDRNv25yKPWWm6dqApNxm1Zb1m5gGcBWYfbsPjTr2v5joit8Af2Zp5P'
-            '6yz3jMbycrLrRMpeAJxR8qDg8'
+            b'xprv9s21ZrQH143K2dyhK7SevfRG72bYDRNv25yKPWWm6dqApNxm1Zb1m5gGcBWYfbsPjTr2v5joit8Af2Zp5P'
+            b'6yz3jMbycrLrRMpeAJxR8qDg8'
         )
         self.assertEqual(
             account.public_key.extended_key_string(),
-            'xpub661MyMwAqRbcF84AR8yfHoMzf4S2ct6mPJtvBtvNeyN9hBHuZ6uGJszkTSn5fQUCdz3XU17eBzFeAUwV6f'
-            'iW44g14WF52fYC5J483wqQ5ZP'
+            b'xpub661MyMwAqRbcF84AR8yfHoMzf4S2ct6mPJtvBtvNeyN9hBHuZ6uGJszkTSn5fQUCdz3XU17eBzFeAUwV6f'
+            b'iW44g14WF52fYC5J483wqQ5ZP'
         )
         self.assertEqual(
             account.receiving_keys.generate_next_address(),
-            '1PmX9T3sCiDysNtWszJa44SkKcpGc2NaXP'
+            b'1PmX9T3sCiDysNtWszJa44SkKcpGc2NaXP'
         )
-        private_key = account.get_private_key_for_address('1PmX9T3sCiDysNtWszJa44SkKcpGc2NaXP')
+        private_key = account.get_private_key_for_address(b'1PmX9T3sCiDysNtWszJa44SkKcpGc2NaXP')
         self.assertEqual(
             private_key.extended_key_string(),
-            'xprv9xNEfQ296VTRaEUDZ8oKq74xw2U6kpj486vFUB4K1wT9U25GX4UwuzFgJN1YuRrqkQ5TTwCpkYnjNpSoHS'
-            'BaEigNHPkoeYbuPMRo6mRUjxg'
+            b'xprv9xNEfQ296VTRaEUDZ8oKq74xw2U6kpj486vFUB4K1wT9U25GX4UwuzFgJN1YuRrqkQ5TTwCpkYnjNpSoHS'
+            b'BaEigNHPkoeYbuPMRo6mRUjxg'
         )
-        self.assertIsNone(account.get_private_key_for_address('BcQjRlhDOIrQez1WHfz3whnB33Bp34sUgX'))
+        self.assertIsNone(account.get_private_key_for_address(b'BcQjRlhDOIrQez1WHfz3whnB33Bp34sUgX'))
 
         self.assertEqual(
             hexlify(private_key.wif()),
@@ -92,12 +92,12 @@ class TestAccount(unittest.TestCase):
         self.assertEqual(len(account.receiving_keys.addresses), 2)
         self.assertEqual(
             account.receiving_keys.addresses[0],
-            '1PmX9T3sCiDysNtWszJa44SkKcpGc2NaXP'
+            b'1PmX9T3sCiDysNtWszJa44SkKcpGc2NaXP'
         )
         self.assertEqual(len(account.change_keys.addresses), 1)
         self.assertEqual(
             account.change_keys.addresses[0],
-            '1PUbu1D1f3c244JPRSJKBCxRqui5NT6geR'
+            b'1PUbu1D1f3c244JPRSJKBCxRqui5NT6geR'
         )
 
         self.maxDiff = None
diff --git a/tests/unit/test_hash.py b/tests/unit/test_hash.py
index 896337eba..8c7f09c53 100644
--- a/tests/unit/test_hash.py
+++ b/tests/unit/test_hash.py
@@ -1,7 +1,11 @@
-import mock
 from unittest import TestCase
 from torba.hash import aes_decrypt, aes_encrypt
 
+try:
+    from unittest import mock
+except ImportError:
+    import mock
+
 
 class TestAESEncryptDecrypt(TestCase):
 
diff --git a/tests/unit/test_wallet.py b/tests/unit/test_wallet.py
index 992a6dee6..09d0bf884 100644
--- a/tests/unit/test_wallet.py
+++ b/tests/unit/test_wallet.py
@@ -86,12 +86,12 @@ class TestWalletCreation(unittest.TestCase):
         self.assertEqual(len(account.receiving_keys.addresses), 2)
         self.assertEqual(
             account.receiving_keys.addresses[0],
-            '1PmX9T3sCiDysNtWszJa44SkKcpGc2NaXP'
+            b'1PmX9T3sCiDysNtWszJa44SkKcpGc2NaXP'
         )
         self.assertEqual(len(account.change_keys.addresses), 1)
         self.assertEqual(
             account.change_keys.addresses[0],
-            '1PUbu1D1f3c244JPRSJKBCxRqui5NT6geR'
+            b'1PUbu1D1f3c244JPRSJKBCxRqui5NT6geR'
         )
         wallet_dict['coins'] = {'btc_mainnet': {'fee_per_byte': 50}}
         self.assertDictEqual(wallet_dict, wallet.to_dict())
diff --git a/torba/account.py b/torba/account.py
index ea480c505..b166fcd3b 100644
--- a/torba/account.py
+++ b/torba/account.py
@@ -102,11 +102,11 @@ class Account:
             'seed': self.seed,
             'encrypted': self.encrypted,
             'private_key': self.private_key if self.encrypted else
-                           self.private_key.extended_key_string(),
-            'public_key': self.public_key.extended_key_string(),
-            'receiving_keys': [hexlify(k).decode('iso-8859-1') for k in self.receiving_keys.child_keys],
+                           self.private_key.extended_key_string().decode(),
+            'public_key': self.public_key.extended_key_string().decode(),
+            'receiving_keys': [hexlify(k).decode() for k in self.receiving_keys.child_keys],
             'receiving_gap': self.receiving_keys.minimum_gap,
-            'change_keys': [hexlify(k).decode('iso-8859-1') for k in self.change_keys.child_keys],
+            'change_keys': [hexlify(k).decode() for k in self.change_keys.child_keys],
             'change_gap': self.change_keys.minimum_gap
         }