It is not possible for WebCal.Guru to push calendars onto your device. Your calendar will update as soon as your calendar application downloads the new data. Usually this happens within a day or at most within a week.
However, not all Android calendar applications handle calendar downloads properly. They may not support them at all, or at least not fully. This can remedied by directing the calendars through Google Calendar, or by using a third-party application ICSx⁵.
First make sure that the calendar has not updated recently. To do this, open an event and see its description. The time that calendar was created will be shown by the Updated label.
Please note that the date is when the calendar content was created, not when it was downloaded. This means that the updated date may not be the current day or the day before it, but it should not be further than a few days in the past.
If the calendar has not updated recently and you are using an Android device, try one of the following.
Updated Tue, 28 Feb 2023 19:30:31 +0000 UTC