Update Erlang releases for build matrix
diff --git a/.travis.yml b/.travis.yml
index 2c6b2f0..d613012 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -19,11 +19,11 @@
 
 matrix:
    include:
+      - otp_release: 18.1
+        python: 2.7
       - otp_release: 17.5
         python: 2.7
       - otp_release: R16B03-1
         python: 2.7
-      - otp_release: R14B04
-        python: 2.7
 
 cache: apt