org-use-effective-time

org-use-effective-time is a variable defined in `org.el'.
Its value is

nil

Documentation:
If non-nil, consider `org-extend-today-until' when creating timestamps.
For example, if `org-extend-today-until' is 8, and it's 4am, then the
"effective time" of any timestamps between midnight and 8am will be
23:59 of the previous day.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.1 of Emacs.