The label relayed, "HOTSHOT's leader Junhyuk will be enlisting as an active duty soldier on January 28, 2020. Due to Junhyuk's wishes to enlist quietly after saying farewell to his family, the time and location of his enlistment will be kept private. As a result, we ask for fans' understanding that there will be no particular event prepared to bid him farewell."
Junhyuk also relayed a handwritten letter to fans through his label, which you can find below. Best of luck to him during his mandatory military service.