The official firmware for Leagoo KIICAA Power T591 and T592 is based on Android 5.1 (Lollipop). You can download the latest official firmware from the Leagoo website or other reputable sources. To flash the official firmware, you'll need to use a tool like SP Flash Tool or Odin.
To install TWRP recovery on your Leagoo KIICAA Power T591 or T592, you'll need to: The official firmware for Leagoo KIICAA Power T591