docs(self-managed): camunda helm chart v8.3 updates

docs/self-managed/platform-deployment/helm-kubernetes/upgrade.md

@@ -95,6 +95,8 @@ For more details on the Keycloak upgrade path, you can also read the [Bitnami Ke
 
 ### v8.3
 
+#### Zeebe
+
 :::caution Breaking change
 
 Zeebe now runs as a non-root user by default.
@@ -131,6 +133,50 @@ zeebe:
     runAsUser: 0
 ```
 
+#### Elasticsearch 8
+
+Firstly, make sure to follow the official [upgrade guide](https://www.elastic.co/guide/en/elasticsearch/reference/8.10/setup-upgrade.html) for Elasticsearch. This is also a good time to make sure you are not using any deprecated values when upgrading.
+
+##### Default values.yaml
+
+If you are using our default values.yaml, then no change is required from your side. You can follow the upgrade steps as normal with the updated default values.yaml.
+
+##### Custom values.yaml
+
+If you have a custom values.yaml, please take note of the following:
+
+Change the image repository and tag:
+
+```yaml
+image:
+  repository: bitnami/elasticsearch
+  tag: 8.10.2
+```
+
+Setting the persistent volume size of the master nodes can’t be done using the volumeClaimTemplate anymore. It must be done using the master values:
+
+```yaml
+master:
+  masterOnly: false
+  heapSize: 1024m
+  persistence:
+    size: 64Gi
+```
+
+Setting a retentionPolicy for elasticsearch values can't be done anymore. You must set the retentionPolicy in the respective components instead. For example, here is an elasticsearch retentionPolicy for the Tasklist component:
+
+```yaml
+retention:
+  enabled: false
+  minimumAge: 30d
+```
+
+In the global section, you can modify the host to show to release-name as well:
+
+```yaml
+host: "{{ .Release.Name }}-elasticsearch"
+```
+
 ### v8.2.9
 
 #### Optimize