diff --git a/docs/reference/release-notes/spaces.md b/docs/reference/release-notes/spaces.md
index ad451c8e..91856d90 100644
--- a/docs/reference/release-notes/spaces.md
+++ b/docs/reference/release-notes/spaces.md
@@ -219,6 +219,37 @@ Any important warnings or necessary information
 - Default resource requests added to `external-secrets-operator` Deployments.
 - Spaces Apollo image registry updated to `xpkg.upbound.io/spaces-artifacts`.
 
+## v1.15.4
+
+### Release Date: 2026-05-22
+
+:::info
+**Up CLI:** The `up space mirror` command in up CLI was updated with new images for this Spaces version. Use up CLI v0.48.3 or later.
+:::
+
+#### Important Changes
+
+- Upgrade the OpenTelemetry Operator to v0.139.0 or later before you upgrade
+  Spaces. This release updates OpenTelemetry dependencies in the
+  `opentelemetry-collector-spaces` image, which require that operator version.
+
+#### What's Changed
+
+- Bumped control plane Kubernetes version to v1.31.14
+- Control plane images updated (VCluster, CoreDNS, etcd, external-secrets-operator).
+- Updated the Spaces Router Envoy image and mxp-charts.
+- Kube-state-metrics and Vector are not installed unless legacy loop-based
+  billing is enabled (`billing.enabled`); on upgrade, existing deployments are
+  uninstalled under the same condition.
+- XGQL is disabled by default and is no longer required to connect a Space
+  (`controlPlanes.uxp.xgql.enabled`).
+- Resolved CVEs in `opentelemetry-collector-spaces` and `hyperspace` images.
+- Bumped Apollo (Query API) to v0.4.12
+
+#### Bug Fixes
+
+- Pausing and resuming now works correctly for UXP v2 control planes.
+
 ## v1.15.3
 
 ### Release Date: 2026-3-16