So please tell me if I'm just missing something here, but here is the issue.
We need the browser/os tags to be captured. I was under the impression that these were captured via the init? Maybe I'm wrong here. Any ideas?
In 1.7 servlet integration was baked into the Sentry Code. Starting from 3.x there is a separate module for servlet integration. If you use Spring or Spring Boot, you should look into dedicated modules for these.