diff --git a/.travis.yml b/.travis.yml
index a76ff72..965d84c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,6 +2,9 @@ language: julia
 julia:
   - nightly
   - 1.3
+env:
+  - RUNTIME_VERSION=3.1
+  - RUNTIME_VERSION=2.2
 
 before-install:
   - wget -q https://packages.microsoft.com/config/ubuntu/16.04/packages-microsoft-prod.deb -O packages-microsoft-prod.deb
@@ -9,4 +12,4 @@ before-install:
   - sudo apt-get update
   - sudo apt-get install apt-transport-https
   - sudo apt-get update
-  - sudo apt-get install dotnet-runtime-3.1
+  - sudo apt-get install dotnet-runtime-$RUNTIME_VERSION