With its high data rates and electromagnetic interference-free operation capability, visible light communication (VLC), also known as LiFi, has emerged as a potential candidate for 6G and beyond networks. In this demo, we present an experimental demonstration of a LiFi system on a software-defined platform. The physical layer of the demo system builds upon direct current biased optical OFDM (DCO-OFDM) and supports adaptive transmission with different modulation schemes/levels including BPSK, 4-QAM, 8-PSK, 16-QAM and 64-QAM. For switching between different modulation schemes, a feedback link with on/off keying modulation is used to send channel state information (CSI) to the OFDM transmitter. Based on the CSI, the OFDM transmitter adapts its next transmission by selecting a modulation scheme which maximizes the spectral efficiency while satisfying a predefined error performance target of 3.8 × 10-3