diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 43a56fa..1612035 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -1,3 +1,7 @@
+0.12.3 (2016-07-27)
+-------------------
+- Fix coverage command invocation to be compatible with coverage v4.2
+
 0.12.2 (2016-07-15)
 -------------------
 - make "service_name" default to "unknown" when not found in registry
diff --git a/setup.py b/setup.py
index 03d9c11..a1b67c0 100644
--- a/setup.py
+++ b/setup.py
@@ -4,7 +4,7 @@
 from setuptools import find_packages
 from setuptools import setup
 
-__version__ = "0.12.2"
+__version__ = "0.12.3"
 
 setup(
     name='pyramid_zipkin',
diff --git a/tox.ini b/tox.ini
index 7899c61..5c64e88 100644
--- a/tox.ini
+++ b/tox.ini
@@ -6,7 +6,7 @@ deps = -rrequirements-dev.txt
 commands =
     coverage erase
     coverage run --source=pyramid_zipkin/ -m pytest -vv {posargs:tests}
-    coverage combine
+    coverage combine --append
     coverage report -m --show-missing --fail-under 100
 
 [testenv:flake8]