diff --git a/.travis.yml b/.travis.yml
index 629bec87..882f98d2 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -30,6 +30,17 @@ matrix:
           packages: ['g++-5', 'valgrind']
       env: COMPILER=g++-5
 
+#    - os: linux
+#      compiler: gcc
+#      addons:
+#        apt:
+#          sources: ['ubuntu-toolchain-r-test']
+#          packages: ['g++-6', 'valgrind']
+#      env: COMPILER=g++-6
+
+    # Clang 3.5 is not able to compile the code,
+    # see https://travis-ci.org/nlohmann/json/jobs/126720186
+
     - os: linux
       compiler: clang
       addons:
@@ -45,23 +56,61 @@ matrix:
           sources: ['ubuntu-toolchain-r-test', 'llvm-toolchain-precise-3.7']
           packages: ['clang-3.7', 'valgrind']
       env: COMPILER=clang++-3.7
+
+    - os: linux
+      compiler: clang
+      addons:
+        apt:
+          sources: ['ubuntu-toolchain-r-test', 'llvm-toolchain-precise-3.8']
+          packages: ['clang-3.8', 'valgrind']
+      env: COMPILER=clang++-3.8
+
+    - os: linux
+      compiler: clang
+      addons:
+        apt:
+          sources: ['ubuntu-toolchain-r-test', 'llvm-toolchain-precise']
+          packages: ['clang-3.9', 'valgrind']
+      env: COMPILER=clang++-3.9
+
+    - os: osx
+      osx_image: beta-xcode6.1
+      compiler: clang
+      env: COMPILER=clang
+
+    - os: osx
+      osx_image: beta-xcode6.2
+      compiler: clang
+      env: COMPILER=clang
+
+    - os: osx
+      osx_image: beta-xcode6.3
+      compiler: clang
+      env: COMPILER=clang
+
+    - os: osx
+      osx_image: xcode6.4
+      compiler: clang
+      env: COMPILER=clang
+
+    - os: osx
+      osx_image: xcode7.1
+      compiler: clang
+      env: COMPILER=clang
      
-   # - os: osx
-   #   compiler: clang
-   #   env: COMPILER=clang
-   #   before_install:
-   #     - brew update
-   #     - brew install valgrind
+    - os: osx
+      osx_image: xcode7.2
+      compiler: clang
+      env: COMPILER=clang
+
+    - os: osx
+      osx_image: xcode7.3
+      compiler: clang
+      env: COMPILER=clang
 
 script:
   - make CXX=$COMPILER CXXFLAGS="-lstdc++"
   - ./json_unit "*"
-  - valgrind --error-exitcode=1 --leak-check=full ./json_unit
-
-notifications:
-  webhooks:
-    urls:
-      - https://webhooks.gitter.im/e/f1196addb0e97a5ff396
-    on_success: change
-    on_failure: always
-    on_start: never
+  - if [ `which valgrind` ]; then
+    valgrind --error-exitcode=1 --leak-check=full ./json_unit ;
+    fi