In April 2019, ioTube v1 was launched as part of Mainnet Alpha to enable conversions of IOTX-E (ERC20) on Ethereum to native IOTX on IoTeX. In August 2020, ioTube v2 introduced “witnesses” to facilitate the conversion of a variety of ERC20 assets including ETH, WBTC, BUSD, PAXG, and UNI. In February 2021, ioTube v3 was launched to unify v1+v2 with significantly lower transfer/settlement costs for cross-chain token transfers. ioTube v4 builds upon this foundation and is our largest cross-chain upgrade yet!