@elidorio
You need a find/replace tool(text crawler):
1. set your project folder
2. set the filters(*.pas; *.pp; *.lfm)
3. search for TDBDateTimePicker then replace with TDBZVDateTimePicker.
3. should be "search for TDBZVDateTimePicker then replace with TDBDateTimePicker."
OR BETTER search for ZVDateTimePicker and replace with DateTimePicker (this will in one move replace all TZVDateTimePickers with TDateTimePickers and all TDBZVDateTimePickers with TDBDateTimePickers, and also will conveniently replace control names on your forms - eg. ZVDateTimePicker1 will become DateTimePicker1).
After this you should manually change properties/methods there are no longer valid, because of the different component.
There shouldn't be any.
Plus, open Project Inspector (Project->Project Inspector in main menu) and remove dependency of ZVDateTimeCtrls package. Then uninstall ZVDateTimeCtrls from the IDE, you will not need it any more.