When the duration is one day,end_date Should be yyyy-mm-yy , 23:59:59

How to make config ,end_date as 23:59:59 when duration is One or more days?

for example:
start_date:2020-04-22 00:00:00 duration:1 end_date:2020-04-22 23:59:59
not :end_date:2020-04-23 00:00:00
start_date:2020-04-22 00:00:00 duration:2 end_date:2020-04-23 23:59:59

Hello Romayn,
Gantt stores the dates in non-inclusive format, there is no way to change how it works.
You can only change what is displayed for the users by using the templates:
Here is an example: