diff --git a/.travis.yml b/.travis.yml
index fdf4c4573e..145f6e43c3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,7 +10,7 @@ services:
 
 env:
     global:
-        - BUILD_RELEASE_MONO_VERSION=6.6.0
+        - BUILD_RELEASE_MONO_VERSION=5.20.1
         - DOCKERHUB_USERNAME=kspckanbuilder
         - secure: "UGXJG9jB9tGwjJXxG0Beu4Poz0leuiCBItnfTTKRm1a/NxXf1eoOH9p9icY5Ur2xHwqh0uWSznuL2aNr58CXtzTcMpXrcUhRsO63FB3Cz6tSdZEb+pKQJ23zmC9929DklKRGUT2D/eBcJcnV+/eAtkarrfLBU1avUQAVJgqXvMI="
         - AWS_DEFAULT_REGION=us-west-2
@@ -31,10 +31,10 @@ matrix:
     include:
         - env: BUILD_CONFIGURATION=Debug_NetCore
           # Cake is broken on Mono 6.8.0
-          mono: 6.6.0
+          mono: 5.20.1
           dotnet: 3.1.1
         - env: BUILD_CONFIGURATION=Release_NetCore
-          mono: 6.6.0
+          mono: 5.20.1
           dotnet: 3.1.1
 
 addons: