**As** a project admin
**I want to** define the working days of the week for my OpenProject instance
**so that** weekends are correctly displayed and taken into account in all modules that involve dates (date picker, GANTT, team planner, calendar...).

**Acceptance criteria**

* The icon for this entry is the existing "**icon-calendar**" (visible in the sidebar and on the overview pages).
* The page has a title: "Working days"
* Begin of the insertionThere is an orange warning toast that is permanently visible:
* With icon 'warning'
* End of the insertion Text: Begin of the insertion"Changing which days of the week are considered working days can affect the start and finish days of all work packages in all projects in this instance."
* Text:End of the insertion
* **Define the working days of the week**
Non-working days are skipped when scheduling work packages and are excluded when calculating duration. Begin of the insertionThisEnd of the insertion Begin of the deletion TheseEnd of the deletion can be overriden at a work-package level.
* This is followed by the horizontal row of checkboxes, one for each day of the week.
* Monday–Friday are selected by default.
* Saturday and Sunday are unselected by default.
* **Mobile:** On smaller screens, the list become vertical, with only one element per line.
* A save button Begin of the insertionis presentEnd of the insertion Begin of the deletion exists and worksEnd of the deletion like on Begin of the insertionanyEnd of the insertion Begin of the deletion every otherEnd of the deletion settings Begin of the insertionpage, except:
End of the insertion Begin of the deletion page.

**Added 18 August:**

End of the deletion * Begin of the insertionIf there was a change in the selection of working days (a new day checked or an old day unchecked), clicking on Save will display a modal dialogue:
* Header title: "Change working days" 
* with divider under header
* Modal text: 
* "Changing which days of the week are considered working days can affect the start and finish days of all work packages in all projects in this instance. 

Are you sure you want to to continue?"
* Primary button (danger): "Change working days" (same string as header)
* Secondary button (white): Cancel



* End of the insertion When an admin makes a change to which dates are considered non-working days (checking or unchecking one or several days), they Begin of the insertionareEnd of the insertion Begin of the deletion should beEnd of the deletion warned that since this is an instance-level setting that might (and almost certainly will) affect the scheduling of work packages in all projects. This Begin of the insertionwarning, although redundant with theEnd of the insertion warning Begin of the insertiontoast already on the page, is importantEnd of the insertion Begin of the deletion hasEnd of the deletion to make Begin of the deletion this potential consequence abundantly clear, since:
* End of the deletion the Begin of the insertionpotentialEnd of the insertion Begin of the deletion admin cannot preview theseEnd of the deletion consequences Begin of the deletion to schedulingEnd of the deletion of Begin of the insertionaEnd of the insertion Begin of the deletion thisEnd of the deletion change Begin of the insertionabundantly clear, sinceEnd of the insertion Begin of the deletion
* End of the deletion the change Begin of the insertionis not easily undoable, and lotsEnd of the insertion Begin of the deletion has the potentialEnd of the deletion of Begin of the insertionusers are likely to suddently getEnd of the insertion Begin of the deletion triggerEnd of the deletion a large number of Begin of the insertionnotifications.

**Visuals**

_Admin settings to configure working daysEnd of the insertion Begin of the deletion notifications for a large numberEnd of the deletion of Begin of the insertionthe week:_

<img class="op-uc-image op-uc-image_inline" src="/api/v3/attachments/38205/content">

_Modal dialogue askingsEnd of the insertion users Begin of the deletion
* **The product team are currently working on specifying howEnd of the deletion to Begin of the insertionconfirm the change_End of the insertion Begin of the deletion display this warning.**End of the deletion

Begin of the deletion **Visuals**

End of the deletion <img class="op-uc-image op-uc-image_inline" Begin of the insertionsrc="/api/v3/attachments/38206/content">End of the insertion Begin of the deletion src="/api/v3/attachments/36808/content">End of the deletion

**Figma**

https://www.figma.com/file/SMzHAQWcY9k0PkTEKd5UQn/Duration-and-Non-Working-Days?node-id=1667%3A46400