Redmine

We really like a gauge that displays status of tickets per version.

Not all systems have versions, not all tickets are assigned a version.

If: there are multiple versions in a project
show one extra bar (?last or first?) for all tickets without version

If: there are no versions in a project
show roadmap like bar on project overview

A visual bar of project completion is a great project status indicator. Not seeing it when there is no version (per project or on a ticket) makes harder to know how much work in project is left.