After upgrade to Virtual Office Mobile app version 7.2, message history in the app does not go back earlier than mid-February 2018.
Virtual Office Mobile v 7.2 (both Android and iOS)
To review Virtual Office messages earlier than mid-February 2018, please log in to the Virtual Office Online interface in your computer's web browser at https://sso.8x8.com/login/uc.
8x8 is moving to a New Chat Experience, and only history after the transition to the new messaging platform is available.
This also affected SMS history prior to April 24, 2018.