Windows 10 and excel 2016 has got Persian calendar and we are excited. Office 2016 hasn't got and we need it very much in mail and calendar and task sections.

When I import an electronic calendar to Outlook 2016 it would be helpful to be able to set reminders for the multiple events imported, rather than having to edit each individual event

When viewing saved emails from Outlook 2016 in windows explorer using the preview pane, the feature to see whether an email contains an attachment has been removed for Outlook 2013.

I'd like to see this option added back.

By default when you create a new recurring meeting in Outlook the default recurrence pattern is "No end date" which is not recommended. Microsoft recommends setting end dates in their best practices link; https://support.office.com/en-us/article/Best-practices-when-using-the-Outlook-Calendar-d93f72d3-2361-4e0d-8d6a-5c4939c17f39?CorrelationId=e84b1b4d-dc2e-4bc7-8b5d-8b386f50d050&ui=en-US&rs=en-US&ad=US

Would like the ability to index only a subset of Outlook folders

It would be good to have something like start menu used to have where you could LOCK the bar so that if you click on the edge you would not change the size of it. Here you would lock headers so that if you click on one by mistake, emails don't get re-sorted.

When creating an event allow sending a notification to the user so that they can get to know when was the even email notification was received.

The follow up flags are great and I often use the tomorrow option to push non urgent tasks until tomorrow, however when my tasks are work-related, pushing from Friday to Saturday just creates a bunch of tasks to move again to Monday on my Saturday morning! Having an option to push the task to 'Next Working Day' would solve this problem if it were available.... I often have around 100-200 tasks so this may not be as significant a problem for those who have a lot less!

The horizontal spacing of the Quick Access Toolbar (QAT) icons dramatically increased with the download of Office Outlook 2016. I can no longer see many of the important QAT icons and using the program is significantly less efficient now. Please restore the ability to display QAT icons in a narrow format. I will not download Office 2016 on my desktop until this issue is resolved because it is so significant. I am considering rolling back my laptop to Office 2013 until the issue is resolved.

We already have GPOs to enable caching in Outlook but these settings are valid for all accounts added. It would make sense to have distinct settings for the default account where I would e.g. cache items for 24 month but for all other accounts maybe only 3 to 12 months for performance reasons regarding OST files.

A feature to select a mail-thread to be auto-archived automatically. This will not affect other mail-threads among the same users of the distribution list.
Use case 1: Large DL is used for different topics with high volume of replies. Topics that are not of importance can be auto-archived to prevent cluttering of your inbox.
Use case 2: Next to auto-archive function a thumbs up can be added. This way the DL knows if the topic is useful or not and is worthwhile to eloborate even more in a follow-up discussion.

When saving Quick Access Toolbar commands, can each ui be saved into one ui. It would be so much easier then saving changes individually or copying the .ui files. Thanks

Have the option to turn on a small questionnaire (a few questions using Likert scales) to get feedback about calendar appointments and tasks. Then use metadata about the meeting, who it was with/category/time/day/etc, and use this to make suggested meetings based on information gathered from emails or OneNote notes.

For users that are on Office 365 for Business, having Delve insights added automatically to meetings would be great.

If IMessage::SubmitError fails and returns MAPI_E_EXTENDED_ERROR, IMessage::GetLastError gets called. If you supply MAPIERROR structure to Outlook it does not use the information on MAPIERROR in the displayed error box. I think the information returned by GetLastError should be shown in the error message popup.
See: https://social.msdn.microsoft.com/Forums/office/en-US/96ca73d6-e4d4-462e-9791-d3e035b288ff/mapi-extended-errors-for-imessage?forum=outlookdev#8803715e-ac2f-4788-b2ad-74eca08b8723

The current settings in the GPOs allow only a fixed cache period, which is now in Outlook 2016 more granular, what is great. But it woulod be beneficial to have two GPO settings regarding this:
1. The time frame of caching in month (existing)
2. If the user can change this within the defined time frame
So for example the GPO fixes 12 month caching, but with the second option, the user could lower to 6 month, but not beyond the 12 month.