diff --git a/.travis.yml b/.travis.yml
index 65521a142..105b20b43 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -23,6 +23,8 @@ jobs:
       install:
         - pip install tox-travis
       script: tox
+    - <<: *tests
+      python: "3.6"
     - <<: *tests
       env: TESTTYPE=integration
 
diff --git a/torba/server/db.py b/torba/server/db.py
index d594cbff0..0d0001abd 100644
--- a/torba/server/db.py
+++ b/torba/server/db.py
@@ -21,7 +21,7 @@ from struct import pack, unpack
 import attr
 from aiorpcx import run_in_thread, sleep
 
-import torba.server.util as util
+from torba.server import util
 from torba.server.hash import hash_to_hex_str, HASHX_LEN
 from torba.server.merkle import Merkle, MerkleCache
 from torba.server.util import formatted_time
diff --git a/torba/server/history.py b/torba/server/history.py
index 5554c3dd1..00d746baf 100644
--- a/torba/server/history.py
+++ b/torba/server/history.py
@@ -15,7 +15,7 @@ import time
 from collections import defaultdict
 from functools import partial
 
-import torba.server.util as util
+from torba.server import util
 from torba.server.util import pack_be_uint16, unpack_be_uint16_from
 from torba.server.hash import hash_to_hex_str, HASHX_LEN
 
diff --git a/torba/server/peer.py b/torba/server/peer.py
index 7b392acbe..850e6bf75 100644
--- a/torba/server/peer.py
+++ b/torba/server/peer.py
@@ -27,8 +27,8 @@
 
 from ipaddress import ip_address
 
+from torba.server import util
 from torba.server.util import cachedproperty
-import torba.server.util as util
 
 from typing import Dict
 
diff --git a/torba/server/session.py b/torba/server/session.py
index 787302075..b8e84881e 100644
--- a/torba/server/session.py
+++ b/torba/server/session.py
@@ -26,11 +26,10 @@ from aiorpcx import (
 )
 
 import torba
-import torba.server.text as text
-import torba.server.util as util
+from torba.server import text
+from torba.server import util
 from torba.server.hash import (sha256, hash_to_hex_str, hex_str_to_hash,
                                 HASHX_LEN, Base58Error)
-from torba.server.peer import Peer
 from torba.server.daemon import DaemonError
 from torba.server.peers import PeerManager
 
diff --git a/torba/server/storage.py b/torba/server/storage.py
index 859b26ffd..4cb8edde9 100644
--- a/torba/server/storage.py
+++ b/torba/server/storage.py
@@ -10,7 +10,7 @@
 import os
 from functools import partial
 
-import torba.server.util as util
+from torba.server import util
 
 
 def db_class(name):
diff --git a/torba/server/text.py b/torba/server/text.py
index 409276f8e..7677353ca 100644
--- a/torba/server/text.py
+++ b/torba/server/text.py
@@ -1,6 +1,6 @@
 import time
 
-import torba.server.util as util
+from torba.server import util
 
 
 def sessions_lines(data):
diff --git a/tox.ini b/tox.ini
index f6b874966..3dad60de0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 #envlist = unit,integration-{torba.coin.bitcoincash,torba.coin.bitcoinsegwit}
-envlist = py37-unit,py37-integration-torba.coin.bitcoinsegwit
+envlist = py{37,36}-unit,py37-integration-torba.coin.bitcoinsegwit
 
 [travis:env]
 TESTTYPE =