To change several document baselines concurrently, use branches.
For example, you enhance current version of the application and assume that its requirements may be added or modified. However, part of the team can already be occupied with preparation of requirements for the next version. It turns out that you need to have two versions of requirements - for current and for upcoming release. Such scenario can be implemented using branches.
Create a requirement branch based on the document or several documents. Meanwhile, system will facilitate migration of changes from master branch to all its nested branches, simplifying the process of migrating changes from current to upcoming releases.
To track the documentation version branching route, use the Version Tree tab