diff --git a/ldappool/__init__.py b/ldappool/__init__.py
index 29ca665..738cff8 100644
--- a/ldappool/__init__.py
+++ b/ldappool/__init__.py
@@ -250,7 +250,7 @@ class ConnectionManager(object):
         # each one in turn in case of connection failures (server down,
         # timeout, etc.).  URIs can be delimited by either commas or
         # whitespace.
-        for server in re.split('[\s,]+', self.uri):
+        for server in re.split(r'[\s,]+', self.uri):
             tries = 0
             exc = None
             conn = None
diff --git a/lower-constraints.txt b/lower-constraints.txt
index 468138a..504bff9 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -5,9 +5,6 @@ docutils==0.11
 dulwich==0.15.0
 extras==1.0.0
 fixtures==3.0.0
-flake8-docstrings==0.2.1.post1
-flake8==2.5.5
-hacking==0.12.0
 imagesize==0.7.1
 Jinja2==2.10
 linecache2==1.0.0
@@ -16,9 +13,7 @@ mccabe==0.2.1
 openstackdocstheme==1.18.1
 pbr==2.0.0
 pep257==0.7.0
-pep8==1.5.7
 prettytable==0.7.2
-pyflakes==0.8.1
 Pygments==2.2.0
 python-ldap==3.0.0
 python-mimeparse==1.6.0
diff --git a/test-requirements.txt b/test-requirements.txt
index 607f94e..cc72c11 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -3,7 +3,7 @@
 # process, which may cause wedges in the gate later.
 # of appearance.
 
-hacking>=1.1.0,<1.2.0 # Apache-2.0
+hacking>=3.0,<3.1.0 # Apache-2.0
 flake8-docstrings==0.2.1.post1 # MIT
 
 coverage!=4.4,>=4.0 # Apache-2.0