The announcement was made in an email to employees.
"Discretionary time off" is paid time off granted to a professional staff employee for a noteworthy achievement or effort that contributes to the organisation's mission, goals, or objectives.
"How, when, and where we do our jobs has changed dramatically.
The news outlet further reports that the changes will start on January 16th and mean even new Microsoft employees don't need to wait to accrue vacation time anymore.
According to LinkedIn News, the software giant said it adopted the system, which also saves its administrative costs, in response to more flexible work schedules.

Source - NDTV