Use date command:

save to variable:

$ export savedDate=2025-11-03T20:39:00+05:30

add 24hrs to savedDate and store it:

$ export updatedDate=$(date -d "$savedDate + 1 day" +"%Y-%m-%dT%H:%M:%S+5:30")

show result:

$ echo $savedDate && echo $updatedDate 

for more information, use:

$ date --help