Merge pull request #3540 from magda-io/v4-migration-docs-updates

Update 4.0.0.md migration docs

docs/docs/migration/4.0.0.md

@@ -24,11 +24,17 @@ To achieve that:
 - For production deployment, make sure the [opensearch](../../../deploy/helm/internal-charts/opensearch/README.md) chart is configured with sufficient resource and proper node numbers and roles.
 - Set [search-api](https://github.com/magda-io/magda/tree/main/deploy/helm/internal-charts/search-api) Helm Chart config fields:
   - `appConfig.elasticSearch.serverUrl` to `http://elasticsearch:9200`
-    - This ensure all search requests will still go to existing elasticsearch engine after helm deployment
+    - This ensure all search requests will still go to the existing elasticsearch engine after helm deployment
+  - `image.tag` to `3.0.4`
+    - Here, we assume your current MAGDA deployment version is the last v3 version: `v3.0.4`
+- Set [elasticsearch](https://github.com/magda-io/magda/tree/main/deploy/helm/internal-charts/elasticsearch) Helm Chart config fields:
+  - `image.tag` to `3.0.4`
+    - Here, we assume your current MAGDA deployment version is the last v3 version: `v3.0.4`
 - Update the `magda` or `magda-core` chart version number in your deployment and use helm to upgrade your deployment
 - Monitor the progress of index building. You can access `https://<host>/api/v0/reindex/in-progress` API to check the progress. By default, admin role is required.
 - Once the index building is completed, you can
-  - remove the `appConfig.elasticSearch.serverUrl` config value
+  - remove the `appConfig.elasticSearch.serverUrl` config value of `search-api` chart
+  - remove the `image.tag` config value of `search-api` & `elasticsearch` charts
   - remove `tags.elasticsearch` config value
   - Use helm to upgrade your deployment one more time.
     - This will ensure