diff --git a/.travis.yml b/.travis.yml
index db5c751..a5e1804 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,7 @@ node_js:
 install:
   - npm install terser
   - npm install uglifycss
-  - npm install typescript
+  - npm install typescript@3.9.3
   - npm install jest
   - npm install @types/jquery
 script: