Online trading platform Interactive Brokers has added Solana (SOL), Cardano (ADA), Ripple (XRP), and Dogecoin (DOGE) to its platform.The new cryptocurrencies are now available to eligible investors with accounts at Paxos and Zero Hash LLC.Interactive Brokers already offered Bitcoin (BTC), Ethereum (ETH), Litecoin (LTC), and Bitcoin Cash (BCH).With the addition of SOL, ADA, XRP, and DOGE, Interactive Brokers now offers a total of 8 cryptocurrencies on its platform.