I’ve created a newer version of the WordPress Calendar plugin for the AlpineCalendar project. This one has moved to BootStrap 5 and now uses https://sa-si-dev.github.io/virtual-select/ to give category selections.
An example of the plugin in action is available below.
Mon
Tue
Wed
Thu
Fri
Sat
Sun
19
20
21
22
23
24
25
26
27
28
29
30
31