diff --git a/.travis.yml b/.travis.yml
index f69283b0..0d7026b0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -207,26 +207,26 @@ matrix:
     env: LLVM_VERSION=3.8.1
     compiler: clang
 
-  - os: linux
-    addons:
-      apt:
-        sources: llvm-toolchain-trusty-3.9
-        packages: clang-3.9
-    env: COMPILER=clang++-3.9
-
-  - os: linux
-    addons:
-      apt:
-        sources: llvm-toolchain-trusty-4.0
-        packages: clang-4.0
-    env: COMPILER=clang++-4.0
-
-  - os: linux
-    addons:
-      apt:
-        sources: llvm-toolchain-trusty
-        packages: clang-5.0
-    env: COMPILER=clang++-5.0
+#  - os: linux
+#    addons:
+#      apt:
+#        sources: llvm-toolchain-trusty-3.9
+#        packages: clang-3.9
+#    env: COMPILER=clang++-3.9
+#
+#  - os: linux
+#    addons:
+#      apt:
+#        sources: llvm-toolchain-trusty-4.0
+#        packages: clang-4.0
+#    env: COMPILER=clang++-4.0
+#
+#  - os: linux
+#    addons:
+#      apt:
+#        sources: llvm-toolchain-trusty
+#        packages: clang-5.0
+#    env: COMPILER=clang++-5.0
 
 #####################
 # installation step #