upgrade os x travis jobs to use latest image
diff --git a/.travis.yml b/.travis.yml
index f1c3567..61d3b10 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -70,51 +70,51 @@
           env: TOXENV=py3pep8
         - language: generic
           os: osx
-          osx_image: beta-xcode6.3
+          osx_image: xcode7
           env: TOXENV=py26 CRYPTOGRAPHY_OSX_NO_LINK_FLAGS=1
         - language: generic
           os: osx
-          osx_image: beta-xcode6.3
+          osx_image: xcode7
           env: TOXENV=py27 CRYPTOGRAPHY_OSX_NO_LINK_FLAGS=1
         - language: generic
           os: osx
-          osx_image: beta-xcode6.3
+          osx_image: xcode7
           env: TOXENV=py33 CRYPTOGRAPHY_OSX_NO_LINK_FLAGS=1
         - language: generic
           os: osx
-          osx_image: beta-xcode6.3
+          osx_image: xcode7
           env: TOXENV=py34 CRYPTOGRAPHY_OSX_NO_LINK_FLAGS=1
         - language: generic
           os: osx
-          osx_image: beta-xcode6.3
+          osx_image: xcode7
           env: TOXENV=pypy CRYPTOGRAPHY_OSX_NO_LINK_FLAGS=1
         - language: generic
           os: osx
-          osx_image: beta-xcode6.3
+          osx_image: xcode7
           env: TOXENV=py27 CRYPTOGRAPHY_OSX_NO_LINK_FLAGS=0
         - language: generic
           os: osx
-          osx_image: beta-xcode6.3
+          osx_image: xcode7
           env: TOXENV=py26 OPENSSL=0.9.8
         - language: generic
           os: osx
-          osx_image: beta-xcode6.3
+          osx_image: xcode7
           env: TOXENV=py27 OPENSSL=0.9.8
         - language: generic
           os: osx
-          osx_image: beta-xcode6.3
+          osx_image: xcode7
           env: TOXENV=py33 OPENSSL=0.9.8
         - language: generic
           os: osx
-          osx_image: beta-xcode6.3
+          osx_image: xcode7
           env: TOXENV=py34 OPENSSL=0.9.8
         - language: generic
           os: osx
-          osx_image: beta-xcode6.3
+          osx_image: xcode7
           env: TOXENV=pypy OPENSSL=0.9.8
         - language: generic
           os: osx
-          osx_image: beta-xcode6.3
+          osx_image: xcode7
           env: TOXENV=docs
 
 install: