diff --git a/core/drupalci.yml b/core/drupalci.yml
index 2c518bc16d..2f2c9ab13a 100644
--- a/core/drupalci.yml
+++ b/core/drupalci.yml
@@ -18,8 +18,8 @@ build:
       # Update PHPUnit & friends.
       container_command:
         commands:
-          - "sudo -u www-data /usr/local/bin/composer require composer/composer:dev-master --no-progress"
-          - "sudo -u www-data /usr/local/bin/composer update typo3/phar-stream-wrapper mikey179/vfsstream --with-dependencies --no-progress"
+          - "sudo -u www-data /usr/local/bin/composer require composer/composer:dev-master mikey179/vfsstream:2.0.x-dev --no-progress"
+          - "sudo -u www-data /usr/local/bin/composer update typo3/phar-stream-wrapper --with-dependencies --no-progress"
       # run_tests task is executed several times in order of performance speeds.
       # halt-on-fail can be set on the run_tests tasks in order to fail fast.
       # suppress-deprecations is false in order to be alerted to usages of