Yes, for a little bit still.
As per the lifecycle page, GroupWise 18.3.1 Released: 12 Apr 2021 Committed Support Ends: 31 Dec 2022
From experience, there is still some support given if you are a bit behind, but it becomes best effort, and primarily to getting you to the newest version.
Andy of KonecnyConsulting.ca in Toronto
Please use the "Like" and/or "Verified Answers" as appropriate as that helps us all.