diff --git a/core/drupalci.yml b/core/drupalci.yml
index bb2bea991c..374a8baa6e 100644
--- a/core/drupalci.yml
+++ b/core/drupalci.yml
@@ -18,8 +18,7 @@ build:
       # Update PHPUnit & friends.
       container_command:
         commands:
-          - "/usr/local/bin/composer self-update"
-          - "sudo -u www-data /usr/local/bin/composer update composer/composer mikey179/vfsstream --with-dependencies --no-progress"
+          - "sudo -u www-data /usr/local/bin/composer update composer/composer --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
diff --git a/core/includes/install.core.inc b/core/includes/install.core.inc
index e5143bc528..9a4b3bfaae 100644
--- a/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -2323,6 +2323,8 @@ function install_config_import_batch() {
   // Match up the site UUIDs, the install_base_system install task will have
   // installed the system module and created a new UUID.
   $system_site = $sync->read('system.site');
+  // @todo the conditional below is required to get tests pass on PHP 7.4;
+  // find a better solution.
   if ($system_site !== FALSE) {
     \Drupal::configFactory()->getEditable('system.site')->set('uuid', $system_site['uuid'])->save();
   }