How are others dealing with migrating SharePoint on-premises calendar lists to SharePoint Online, given the below requirements? The 3 significant requirements are: 1) Have > 5,000 events, sometimes within a year, 2) Maintain additional non-standard event metadata, and 3) Access that calendar from Outlook. What we've seen is that you can't have that calendar in SharePoint Online, and attach to Outlook because of the 5,000 item threshold. For SharePoint on-premises, we increased the threshold. We've discussed having 2 or more calendars, creating archives. For some groups, this would be a significant impediment to their process.
Manage calendar requirements:
Ability to have > 5,000 events in the calendar and attach that calendar to Outlook
Drag / drop calendar entries onto SharePoint calendar from other Outlook calendars
Track metadata for each calendar event (e.g., specific customer, specific devices)
30 day & week view of calendar entries, if viewing from SharePoint.
Keep history of calendar entries for specific people
Have a workflow of data decisions and approvals for each scheduled event that involves actions by multiple people
Streamlined data entry form, if managing data entry from SharePoint