diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index afbc6bf948627b75548d60015703917f36c2f705..1862dea825bec36784bd655097df738803b3a3bb 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -304,6 +304,6 @@ upgradetest:debian-stretch-aegir3-apt-upgrade:
     - sudo su aegir --login --command 'drush @hostmaster php-eval "echo hosting_task_count_running();"'
     # upgrade to the latest version from the unstable repo.
     - rm -v /etc/apt/sources.list.d/aegir-stable.list
-    - echo "deb http://debian.aegirproject.org unstable main" | sudo tee -a /etc/apt/sources.list.d/aegir-unstable.list
+    - echo "deb [signed-by=/usr/share/keyrings/aegir-archive-keyring.gpg] http://debian.aegirproject.org unstable main" | sudo tee -a /etc/apt/sources.list.d/aegir-unstable.list
     - sudo apt-get update
     - sudo apt-get --yes dist-upgrade