Summary

Companion App unable to re-upload the file with some special characters as part of the filename. As far as we know, the below characters are not working:

[ ] +

Environment

Confluence Server 7.4.6 (Latest LTS)
Atlassian Companion App 1.2.5 (Latest Release)

Steps to Reproduce

1. Create a test page
2. Upload the [atlassian] test.xlsx as an attachment
3. Open it from Companion App
4. Update the content

Expected Results

Able to re-upload the new version

Actual Results

Upload button greyed out, unable to re-upload to Confluence

Workaround

N/A

Notes

We've tried uploading files with some other special characters as part of the file name such as below and they're all working properly:

% $ & ` ! ( ) { } _ - .