The 'not in projects' field was earlier present in the advanced query and filters. This was particularly helpful to view and compare tasks that were in a release but not assigned to a sprint. The field has now gone missing. Any reason why this has happened and if this can be brought back soon? Thanks.
It's still there. :) You only have to type the name of a project in the "Projects" field, and you will get several options, including "Not in". Same features availables, less form fields.