diff --git a/.travis.yml b/.travis.yml
index 54e5b7d8..cd98c0f9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,6 +6,7 @@ compiler:
 env:
     global:
         - LIBSODIUM_VER=1.0.11
+        - MBEDTLS_VER=2.4.0
 before_install:
     - wget https://download.libsodium.org/libsodium/releases/libsodium-$LIBSODIUM_VER.tar.gz
     - tar xvf libsodium-$LIBSODIUM_VER.tar.gz
@@ -13,9 +14,9 @@ before_install:
     - ./configure --prefix=/usr && make
     - sudo make install
     - popd
-    - wget https://tls.mbed.org/download/mbedtls-2.4.0-gpl.tgz
-    - tar xvf mbedtls-2.4.0-gpl.tgz
-    - pushd mbedtls-2.4.0
+    - wget https://tls.mbed.org/download/mbedtls-$MBEDTLS_VER-gpl.tgz
+    - tar xvf mbedtls-$MBEDTLS_VER-gpl.tgz
+    - pushd mbedtls-$MBEDTLS_VER
     - make
     - sudo make install
     - popd