Issue Summary

Jira calendar under Backlog screen doesn't respect ISO8601 standard in Date Picker setting under Look & Feel

Steps to Reproduce

• Navigate to Administration > System > Look and Feel and set use ISO8601 formatting for date pickers to Yes.
• Navigate to an existing or create a new Agile Scrum board.
• Create a version using the Release sidebar under Backlog view.
  
  
• Navigate to Backlog screen and check the calendar under Sprint
  
• Observe that the week number has not changed like the calendar in version screen and it seems it doesn't respect the ISO8601 setting under Look & Feel.

Expected Results

JIRA should consistently use the ISO8601 setting for all the calendars in the respective sections.

Actual Results

Jira Agile does not apply this setting, as a result, the Week number in these calendars in an inconsistent manner.

Notes

This can be seen under:

Board -> Configure -> Working Days -> Non Working Days -> Add Date

Workaround

1. Modify Calendar.setup.js by doing vi to atlassian-jira/includes/lib/calendar/Calendar.setup.js and modify useISO8601WeekNumbers to true
2. Refresh the the resource in the page using disabled cache (Under Developer tools) while reloading the tab.

Above steps will help you fix the sprint board widget(as you will notice after checking the video). Release page is handled by another in-built module and has different way to have iso week Initialized and this gets handled by look and feel settings you already have in place.

If the above step didn't help, kindly do a vi as below and verify that it would be nice:

vi atlassian-jira/includes/lib/calendar/Calendar.setup-min.js

If that is the case, please modify it to !0 instead of !1 to make it true and try reloading the page with cache disabled, that should work.