diff --git a/.travis.yml b/.travis.yml
index 6938b6a..684c922 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,15 +1,20 @@
 language: python
+sudo: false
 python: 3.5
-env:
-  matrix:
-    - TOXENV=py26
-    - TOXENV=py27
-    - TOXENV=py33
-    - TOXENV=py34
-    - TOXENV=py35
-    - TOXENV=hg35
-    - TOXENV=hg36
-    - TOXENV=hg41
-    - TOXENV=coverage
+matrix:
+  include:
+    - python: 2.7
+      env: TOXENV=py27
+    - python: 3.3
+      env: TOXENV=py33
+    - python: 3.4
+      env: TOXENV=py34
+    - python: 3.5
+      env: TOXENV=py35
+    - env: TOXENV=hg35
+    - env: TOXENV=hg36
+    - env: TOXENV=hg41
+    - env: TOXENV=hg42
+    - env: TOXENV=coverage
 install: pip install docutils tox
 script: tox
diff --git a/src/diff_highlight.py b/src/diff_highlight.py
index 4bb2e0d..e8b9dfd 100644
--- a/src/diff_highlight.py
+++ b/src/diff_highlight.py
@@ -14,8 +14,7 @@
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
 
-from hgext import color
-from mercurial import extensions
+from mercurial import extensions, ui, util
 from mercurial.i18n import _
 from highlights.pprint import INSERTED, DELETED, pprint_hunk
 
@@ -25,7 +24,7 @@
 DELETE_EMPH = 'diff.deleted_highlight'
 
 
-class colorui(color.colorui):
+class colorui(ui.ui):
     hunk = None
     tab = None
 
@@ -89,23 +88,37 @@ def uisetup(ui):
         return
 
     try:
-        extensions.find('color')
-    except KeyError:
-        ui.warn(_("warning: 'diff-highlight' requires 'color' extension "
-                  "to be enabled, but not\n"))
-        return
+        from hgext import color as colorext
+
+        try:
+            extensions.find('color')
+        except KeyError:
+            ui.warn(_("warning: 'diff-highlight' requires 'color' extension "
+                      "to be enabled, but not\n"))
+            return
+    except ImportError:
+        colorext = None
+    try:
+        from mercurial import color
+    except ImportError:
+        pass
 
     if not isinstance(ui, colorui):
         colorui.__bases__ = (ui.__class__,)
         ui.__class__ = colorui
 
+    ver = tuple(int(s) if s.isdigit() else s for s in util.version().split('.'))
+
     def colorconfig(orig, *args, **kwargs):
         ret = orig(*args, **kwargs)
 
-        try:
-            from mercurial.color import _styles as styles
-        except ImportError:
+        if ver < (4, 1):
+            styles = colorext._styles
+        elif ver < (4, 2):
             styles = color._styles
+        else:
+            styles = color._defaultstyles
+
         if INSERT_EMPH not in styles:
             styles[INSERT_EMPH] = styles[INSERT_NORM] + ' inverse'
 
@@ -114,4 +127,4 @@ def colorconfig(orig, *args, **kwargs):
 
         return ret
 
-    extensions.wrapfunction(color, 'configstyles', colorconfig)
+    extensions.wrapfunction(colorext if ver < (4, 2) else color, 'configstyles', colorconfig)
diff --git a/tests/test_diff_highlight.py b/tests/test_diff_highlight.py
index 57ce452..f7df1d3 100644
--- a/tests/test_diff_highlight.py
+++ b/tests/test_diff_highlight.py
@@ -7,10 +7,16 @@
     import unittest
 
 if sys.version_info < (3, 0):
+    try:
+        from hgext import color
+
+        colorext = color
+    except ImportError:
+        colorext = None
     try:
         from mercurial import color
     except ImportError:
-        from hgext import color
+        pass
     from diff_highlight import colorui
     from mercurial.util import version as mercurial_version
 else:
@@ -20,12 +26,24 @@
 class TestDiffHighlight(unittest.TestCase):
     @unittest.skipIf(color is None, "mercurial is not supported py3")
     def test_colorui(self):
-        import curses
-        curses.setupterm("xterm", 1)
-        color._styles['diff.inserted_highlight'] = 'green inverse'
-        color._styles['diff.deleted_highlight'] = 'red inverse'
+        try:
+            import curses
+
+            curses.setupterm("xterm", 1)
+        except ImportError:
+            pass
 
         ui = colorui()
+        if mercurial_version() >= "4.2.0":
+            ui.setconfig('ui', 'color', 'always')
+            color.setup(ui)
+            styles = ui._styles
+        else:
+            colorui.__bases__ = (colorext.colorui,)
+            styles = color._styles
+        styles['diff.inserted_highlight'] = 'green inverse'
+        styles['diff.deleted_highlight'] = 'red inverse'
+
         if mercurial_version() >= "3.7.0":
             ui.pushbuffer(labeled=True)
         else:
@@ -44,13 +62,22 @@ def test_colorui(self):
         ui.write(" ", '')
         ui.write("\n", '')
 
-        stop = "\x1b(B\x1b[m"
+        if mercurial_version() >= "4.2.0":
+            stop = "\x1b[0m"
+
+            def start(*colors):
+                return "\x1b[0;" + ";".join(str(c) for c in colors) + "m"
+
+            def restart(*colors):
+                return stop + start(*colors)
+        else:
+            stop = "\x1b(B\x1b[m"
 
-        def start(*colors):
-            return stop + "".join("\x1b[%dm" % c for c in colors)
+            def start(*colors):
+                return stop + "".join("\x1b[%dm" % c for c in colors)
 
-        def restart(*colors):
-            return stop + start(*colors)
+            def restart(*colors):
+                return stop + start(*colors)
 
         if mercurial_version() >= "3.7.0":
             lines = ui.popbuffer().splitlines()
diff --git a/tox.ini b/tox.ini
index c28ba24..d38641c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist=py26,py27,py32,py33,py34,py35,hg35,hg36,hg41
+envlist=py26,py27,py32,py33,py34,py35,hg35,hg36,hg41,hg42
 
 [testenv]
 deps=
@@ -71,6 +71,12 @@ deps=
     {[testenv:py3_common]deps}
     mercurial<4.2
 
+[testenv:hg42]
+basepython= python2.7
+deps=
+    {[testenv:py3_common]deps}
+    mercurial<4.3
+
 [testenv:coverage]
 basepython= python2.7
 deps=