diff --git a/.travis.yml b/.travis.yml
index c420cc2..2cc9afc 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,6 +2,7 @@ language: ruby
 rvm:
   - 2.2.6
   - 2.3.3
+  - 2.4.0
   - jruby-9.0.5.0
 
 branches:
@@ -13,7 +14,6 @@ addons:
 
 env:
   - REDMINE_VER=2.6-stable
-  - REDMINE_VER=3.1-stable
   - REDMINE_VER=3.2-stable
   - REDMINE_VER=3.3-stable
   - REDMINE_VER=master