unknown command before commands were added

Before 0.16.0, when commands were introduced, typing a command into the chat will display "Unknown command"

• What I expected to happen:The command posted to chat.
• What actually happened:It said "Unknown command."
• Steps to reproduce: 1. Play a version of MCPE before 0.16.0.
  2. Type a command into the chat. (e.g. /give @p minecraft:dirt 64)