Kanban Release for a Planned Fixed Version

Currently, if customer has a pre-defined fixed version (example: version test) and on the GreenHopper Kanban board. If the customer would want to release the issue associated with this pre-defined fixed version, it returns error as the screenshot below:

Kanban board default filter:

fixVersion in unreleasedVersions() OR fixVersion is EMPTY

It should enable the customer to release for unreleased version as well.

Quote from customer:

Therefor issues with an unreleased fix version (because this field is used for planning purpose) will appear on the board but cannot be released!

Steps to Replicate

1. Create a Kanban Board associated with Project
2. Create a version on the project, no release date defined
3. Perform edit on the issues to plan fixing the issue on the newly created version
4. Move all the issues planned to the done column
5. Release and insert the version as planned earlier
6. Noticed error message