diff --git a/src/yunohost/data_migrations/0021_migrate_to_bullseye.py b/src/yunohost/data_migrations/0021_migrate_to_bullseye.py
index 6678fa040..4b40fcbe0 100644
--- a/src/yunohost/data_migrations/0021_migrate_to_bullseye.py
+++ b/src/yunohost/data_migrations/0021_migrate_to_bullseye.py
@@ -36,6 +36,13 @@ class MyMigration(Migration):
 
         logger.info(m18n.n("migration_0021_start"))
 
+        #
+        # Add new apt .deb signing key
+        #
+
+        new_apt_key = "https://forge.yunohost.org/yunohost_bullseye.asc"
+        check_output(f"wget -O- {new_apt_key} -q | apt-key add -qq -")
+
         #
         # Patch sources.list
         #