When could we expect a new version of Annotation library? Beta-version probably?
1.9.0 has a lot of issues which stop us to using it (like problem with CustomInputDataHandler).
Plus it has viewer version 2.8.0 only compare to latest 2.11.0 where you did a caching and performance improvements. When I was trying to use groupdocs-annotation 1.9.0 together with the viewer 2.11.0 I have got a lot of incompatibility errors, seems the only chance is to wait for a new release.