Calender in Codeigniter 4

Hi, currently there are no plans on implementing the Calender library in CodeIgniter 4. That and other libraries where dropped.

If you have the know-how you are more than welcome porting it so it can become an module, as that's our approach now days. Instead of bundling it directly into the framework itself, we will in the future provide features as stand-alone. Keeping CodeIgniter slim as possible.