Unable to Download Previous Versions of Attachments Which Contain Special Characters in Title

Summary

Previous Versions of Attachments uploaded to Confluence that contain a Special Character in their Title cannot be downloaded and generates a "Page Not Found" error

Environment

• Confluence 6.0.0-OD-2016.10

Steps to Reproduce

1. Upload an attachment to a Confluence Page which contains a Special Character; for testing, used a Plus '+' character. Also breaks when file name contains ampersand (&)
2. Modify the file and re-upload it to the same Confluence Page to generate a version
3. Go to the Page's Attachments and click on a Previous Version (say Version 1) to download the previous version

Expected Results

Previous version of the file prompts for download

Actual Results

Page opens in error and indicates "Page Not Found"
No Errors in log

Notes

All versions under the parent (including the "Current") cannot be downloaded from the expanded view showing all versions however the titled Attachment (title of attachment) can be clicked on and downloaded without issues.

Unsure of other special characters which may affect this; have only tested with +

Workaround

Found that the URL displays the following:
https://HOSTNAME/wiki/download/attachments/2654266/Example%20Sheet%20%2B.xlsx?version=1&modificationDate=1457999001396&api=v2

After URL manipulation, found that the &modificationDate=1457999001396& section appears to break the URL.

If it is removed and replaced with a Single Ampersand '&', the previous version file can be downloaded successfully:

https://HOSTNAME/wiki/download/attachments/2654266/Example%20Sheet%20%2B.xlsx?version=1&api=v2

Or

Rename the current version of the file, removing the special character.