diff --git a/.travis.yml b/.travis.yml
index db3eef4..c91ac40 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,6 +9,6 @@ services:
 
 before_script:
   - composer self-update
-  - composer install --no-interaction --prefer-dist --dev
+  - composer install --no-interaction --prefer-source --dev
 
 script: php tests/lint.php src/Kdyby/ tests/KdybyTests/ && VERBOSE=true ./tests/run-tests.sh -s tests/KdybyTests/