Legislation resulted in a change to probationary period that applies only to employees who are appointed to permanent positions in the competitive service in DoD.
“The probationary period for many new civilian employees hired by the Defense Department on or after Nov. 26, 2015, has changed from one year to two years, the acting deputy assistant secretary of defense for civilian personnel policy said.”
https://www.defense.gov/News/Article/Article/961606/dod-announces-new-hire-probationary-period
However, Congress is considering extending it to all civilian employees, which as with all things Congressional may or may not happen and probably would not happen quickly.
“The House of Representatives’ Oversight and Government Reform Committee, the Government Managers Coalition (GMC) and the National Active and Retired Federal Employees Association (NARFE) have asked the committee to consider extending the probationary period covering new federal employees. The committee is expected to consider the proposal in its next scheduled session on January 12, 2016.”