He answers it right here:
NOTICE THE "[I]" IN BRACKETS BELOW…
What rocket fired today?
[i]
Message sent.
Q
▶Anonymous (You) 12/23/17 (Sat) 01:00:03 acccd8 No.154658
The missing "I" from "missle"
Future news will unlock more of the message.
Missing [i] confirmed.
Q