Hi Tim,
We are actively supporting 2.3.x, as well as working on 2.4. While we have no EOL date for 2.3.x, we typically support one version behind the current release version. Our plan is to complete 2.4 and, based on the features, we expect most members of the community to migrate.
We will continue to support 2.3.x as we improve 2.4.x.
Once 2.4 ships, we will be working towards the 2.5 release. Once we ship 2.5 (planned for 2022), you can expect that we will be sunsetting support for 2.3.x.
Regards,... Fred