diff --git a/ansible/roles/rabbitmq/defaults/main.yml b/ansible/roles/rabbitmq/defaults/main.yml
index 4c059eadb0..656689a915 100644
--- a/ansible/roles/rabbitmq/defaults/main.yml
+++ b/ansible/roles/rabbitmq/defaults/main.yml
@@ -88,7 +88,7 @@ rabbitmq_cluster_partition_handling: "pause_minority"
 # The rabbitmq default for ha queues is "when-synced"
 # More details see:
 # https://www.rabbitmq.com/ha.html#promoting-unsynchronised-mirrors
-rabbitmq_ha_promote_on_shutdown:
+rabbitmq_ha_promote_on_shutdown: "always"
 # The number of rabbitmq replicas should follow this advice:
 # https://www.rabbitmq.com/ha.html#replication-factor
 # This means, if you have three rabbit nodes, we request two
diff --git a/releasenotes/notes/rabbitmq-set-ha-promote-on-shutdown-always-e8db9ad15fd1b8fb.yaml b/releasenotes/notes/rabbitmq-set-ha-promote-on-shutdown-always-e8db9ad15fd1b8fb.yaml
new file mode 100755
index 0000000000..71962b3493
--- /dev/null
+++ b/releasenotes/notes/rabbitmq-set-ha-promote-on-shutdown-always-e8db9ad15fd1b8fb.yaml
@@ -0,0 +1,11 @@
+---
+upgrade:
+  - |
+    The RabbitMQ variable `rabbitmq-ha-promote-on-shutdown` now defaults to
+    `"always"`. This only has an effect if
+    `om_enable_rabbitmq_high_availability` is set to `True`. When
+    `ha-promote-on-shutdown` is set to `always`, queue mirrors are promted on
+    shutdown even if they aren't fully synced. This means that value
+    availability over the risk of losing some messages. Note that the contents
+    of the RabbitMQ definitions.json are now changed, meaning RabbitMQ
+    containers will be restarted on next deploy/upgrade.