If upgraded to the last version (5.4.2) and at first I could not see the calendar entries that were visible before the upgrade. After checking the different configuration options for the calendar widget, I found out that my calendar entries were not visible because I had specified a boolean for the all day event. After removing this option (selected 'None'), all calendar entries were visible again.
After some testing I have found out that this problem only seems to happen with non all day events. Calendar entries for all day events were also visible when a boolean had been selected for the all day event, but the other entries were no longer visible. Apparently there is an issue with this option for non all day events.
If upgraded to the last version (5.4.2) and at first I could not see the calendar entries that were visible before the upgrade. After checking the different configuration options for the calendar widget, I found out that my calendar entries were not visible because I had specified a boolean for the all day event. After removing this option (selected 'None'), all calendar entries were visible again.
After some testing I have found out that this problem only seems to happen with non all day events. Calendar entries for all day events were also visible when a boolean had been selected for the all day event, but the other entries were no longer visible. Apparently there is an issue with this option for non all day events.