OBSDOCS-2041 COO 1.2.1 release notes

Author: gabriel-rh

observability/cluster_observability_operator/cluster-observability-operator-release-notes.adoc

@@ -24,6 +24,21 @@ The following table provides information about which features are available depe
 | 1.1+          | 4.18+              | ✔                     | ✔         | ✔                     | ✔          | ✔
 |===
 
+[id="cluster-observability-operator-release-notes-1-2-1_{context}"]
+== {coo-full} 1.2.1
+
+[id="cluster-observability-operator-1-2-1-bug-fixes_{context}"]
+=== Bug fixes
+
+* Before this update, an old version label matcher was retained during the Operator version 1.2 upgrade. This caused Perses dashboards to become unavailable. With this release, the version label is removed and Perses dashboards are correctly reconciled.
+
+[id="cluster-observability-operator-1-2-1-known-issues_{context}"]
+=== Known issues
+
+These are the known issues in {coo-full} 1.2.1:
+
+* Upgrading from version 1.2.0 to 1.2.1 corrupts the monitoring plugin's `UIPlugin` resource, when you have also deployed distributed tracing, the troubleshooting panel, and Advance Cluster Management (ACM), together with the monitoring UI plugin. You can resolve this issue by recreating the UI plugin. (link:https://issues.redhat.com/browse/COO-1051[COO-1051])
+
 [id="cluster-observability-operator-release-notes-1-2_{context}"]
 == {coo-full} 1.2