I will upgrade my 4.3.9 installation of Graylog to the 5.0 version.
In the Opensearch compatibility matrix at https://go2docs.graylog.org/5-0/planning_your_deployment/planning_your_upgrade_to_opensearch.htm I see that Graylog 5.0 is compatible with Opensearch 2.x, but, at the same time, it is compatible with Elasticsearch 7.10.2. So, I suppose that it is compatible with Opensearch 1.x as well. But this is not mentioned in the matrix.
Could someone confirm me the compatibility between Graylog 5.0 and Opensearch 1.x? I need it just for migration, to avoid upgrading Graylog and Opensearch at the same time.