Subscribed calendar not updating for IOS 14 users

ATM the phone needs to be turned off and on again every morning for the Apple calendar to show todays date until the next update

I have a lot of clients saying that some random events aren't being updated by iCal on their phone. It works if they subscribe to the calendar again.

I am currently experiencing this issue on 15.5. Is there a solution to this?

I have installed version 16 and it is still an issue. I’ve managed to escalate the issue with the apple developers, but I did not had any news since. It’s been a month already.

I have two subscriptions two different calendards, one is refreshing, the other one not. I checked the http headers for the different subscriptions and found out that the working one has several cache related http headers set:

< HTTP/1.1 200 Apple WebObjects
< Server: nginx/1.19.2
< Date: Tue, 27 Sep 2022 06:14:34 GMT
< Content-Type: text/calendar
< Content-Length: 11496
< cache-control: private, no-cache, no-store, must-revalidate, max-age=0
< expires: Tue, 27-Sep-2022 05:32:39 GMT
< pragma: no-cache
< x-webobjects-loadaverage: 52
< X-Varnish: 156865840
< Age: 0
< Via: 1.1 varnish (Varnish/6.3)
< X-Cache: MISS
< Accept-Ranges: bytes
< Connection: keep-alive

Could this be (part of) the problem?

Hi, i have the same problem since a long time. Turn the calender off and on isn't a solution.

I just started building a service with subscribed calendars. This is the behavior I noticed:

• When I subscribe one calendar, sometimes this calendar syncs
• When I subscribe a second calendar, the first calendar syncs consistently and the second calendar sometimes syncs
• When I subscribe a third calendar, the first two calendars sync consistently, but the third calendar does not sync (neither initially nor on refetch)
• When I subscribe a fourth calendar, the first three calendars sync consistently, but the fourth calendar does not sync (neither initially nor on refetch)

Conclusion: It looks like there is some kind of off by one bug in the iOS Calendar sync logic. iOS syncs the first n-1 calendars, but not the nth subscribed calendar. The workaround is to add an extra dummy calendar subscription after the subscriptions you care about, but I can't ask this of my intended users. How do we escalate this to Apple?

Other notes:

• By "sync consistently", I mean that I can watch requests come in for the calendar on the service I am building each time I drag down on the Calendars list to force a manual refetch
• I am hosting the service on a local machine right now and I'm not using SSL/https. I have another service that hosts calendars using https, and it has never had issues with syncing as far as I know - but that service only ever syncs one calendar to the iOS device. It was the last sync'd calendar in the list for more than a year without issues.
• I am adding the subscriptions to my iCloud account
• iOS 16.6.1

I fixed the off by one issue I described above by adding // to my webcal url's. The off by one behavior was seen with url's like this:

• webcal:192.168.1.182:8085/wakaan23-aura
• webcal:192.168.1.182:8085/wakaan23-halo

This caused the "Subscribed to" field in the Subscription Details page to show up as "http:192.168.1.182:8085/wakaan23-aura".

After adding //, my webcal url's look like this and all subscribed calendars are requested consistently:

• webcal://192.168.1.182:8085/wakaan23-aura
• webcal://192.168.1.182:8085/wakaan23-halo

Now the "Subscribed to" field in the Subscription Details page shows up as "http://192.168.1.182:8085/wakaan23-aura".

Note to Apple: I suspect the off by one and the lack of // subscription url are related.