Yahoo.com and Outlook.com (online) / Office 365 (online)

On a regular basis, we test the methods for adding events to calendars. We currently have two methods we would like to get back to using - those methods are: 

Outlook.com + Office 365 (direct methods).

• These two methods allow us to send the user directly to their calendar app without having to grant access to our app at Microsoft.
• These methods are getting very close to working again. They have been tested but still fail to produce good content. We’ll continue using the Microsoft Events API for inserting events into the user’s calendar until the issues have been resolved by Microsoft.

Yahoo.com (direct method)

• This method has been out of service since Yahoo updated its calendar service in January 2021. We’ve reworked how we add events to Yahoo and we’re now able to add events again. When we parse date/time to Yahoo all date formats are ignored by Yahoo. Therefore we now on the basis of the user’s IP time zone convert the events date/time to the user’s date/time and parse it to Yahoo Calendar. This leaves some room for errors but for the majority of users, it’ll work as intended.
• We obviously hope Yahoo Calendar and the team responsible for Yahoo Calendar will fix the issues the whole world is experiencing.