v0.18.1 release
diff --git a/CHANGELOG b/CHANGELOG
index 86c24a7..2db1cc0 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,9 @@
+0.18.1
+
+  explicit build-backend workaround for pip build isolation bug
+  "AttributeError: 'module' object has no attribute '__legacy__'" on pip install
+  https://github.com/httplib2/httplib2/issues/169
+
 0.18.0
 
   IMPORTANT security vulnerability CWE-93 CRLF injection
diff --git a/python2/httplib2/__init__.py b/python2/httplib2/__init__.py
index d29193d..f35ba48 100644
--- a/python2/httplib2/__init__.py
+++ b/python2/httplib2/__init__.py
@@ -19,7 +19,7 @@
     "Alex Yu",
 ]
 __license__ = "MIT"
-__version__ = "0.18.0"
+__version__ = "0.18.1"
 
 import base64
 import calendar
diff --git a/python3/httplib2/__init__.py b/python3/httplib2/__init__.py
index f5d7672..cf2db60 100644
--- a/python3/httplib2/__init__.py
+++ b/python3/httplib2/__init__.py
@@ -15,7 +15,7 @@
     "Alex Yu",
 ]
 __license__ = "MIT"
-__version__ = "0.18.0"
+__version__ = "0.18.1"
 
 import base64
 import calendar
diff --git a/setup.py b/setup.py
index d8d9c48..b66d24e 100755
--- a/setup.py
+++ b/setup.py
@@ -4,7 +4,7 @@
 import sys
 
 pkgdir = {"": "python%s" % sys.version_info[0]}
-VERSION = "0.18.0"
+VERSION = "0.18.1"
 
 
 # `python setup.py test` uses existing Python environment, no virtualenv, no pip.