Hi,
The highlightedDates was added in Ionic 6.6.0 (Related PR), so you might check if your installed Ionic framework version is greater than 6.6.0
One thing to notice, the ionic -v command will print the version of @ionic/cli (6.20.9), not the actual installed Ionic framework version.
The proper way to check the version number is by using ionic info command.
- For example, the following project is using Ionic framework version 5.9.4:
