High-level Overview of Lisk Interoperability. Our interoperability solution is based on the paradigm of cross-chain certification introduced in detail in the previous research blog post "Introduction to Blockchain Interoperability". Basically, cross-chain certification means that information from one chain is submitted to another chain utilizing a signed object called a certificate. Any kind of information can be exchanged between chains using general cross-chain messages. The Lisk mainchain plays the key role in the whole ecosystem since all cross-chain messages between sidechains are routed via the mainchain. Sidechains can further be customized, not just regarding the application logic, but also with regard to the general blockchain logic, such as the consensus algorithm. The LSK token can be moved to any chain, and it will be the default token for transaction fees in the ecosystem. Moreover, creating sidechain tokens on a sidechain and transferring them to other chains will be straightforward using the new token standards. The New Roadmap We are organizing our research of the interoperability solution and the LIPs that we are preparing around eight roadmap objectives. Each roadmap objective encompasses one key aspect of our interoperability solution that will be addressed by one or more LIPs. We have updated our roadmap to include these eight objectives for the Blockchain Interoperability phase. More details about these objectives and the LIPs addressing them will be revealed at the next Lisk.js event on May 21st-22nd, 2021.