BTS may be unable to continue performing as a 7 member group at their concerts starting in 2020.
Jin and Suga may have to fulfill their military obligations, and therefore unable to perform with the whole group in world tours. Males who are 25 years old and above in Korea must get official government permission to leave the country.
Jin is currently 27 and by age 28, he must enlist in the military. Suga, who is currently 26, may be unable to tour in the latter half of 2020.
Although the government has acknowledged BTS for their global success, these matters lead to ambiguity regarding the group's future activities as a group overseas. Politicians have even suggested that BTS be exempt from military duties due to their success, but that issue is still currently being debated.