Bulk metadata editing is a new SharePoint Online feature in Office 365. We’ll begin rolling this feature out in the next few days.
How does this affect me?
This feature allows you to edit the metadata of several items at once by selecting those items in the modern list view, and using the details pane to edit their metadata.
We’ll be gradually rolling this out to Targeted Release customers on January 17th, and the roll out will be completed by the end of January.
There is nothing you need to do to prepare for this change. Please click Additional Information to learn more.
Peter BowersSeptember 15, 2018 at 9:19 am
Be aware that there is a bug in this feature which makes it useless if you have boolean columns in your list. For bulk edit to work properly SP has to detect WHICH columns you are editing – which columns should have their value modified for every item selected. But boolean columns only have 2 values and SP doesn’t recognize the difference between a boolean field which was untouched (and therefore “no”) and a boolean field which was intentionally set to “no” – SO IT ALWAYS SETS ALL BOOLEAN FIELDS TO WHATEVER VALUE IS IN YOUR BULK EDIT FORM – there is no way to leave boolean columns untouched.