Is Blockchain a hype or a trend that is here to stay? Based on the increasing interest of blockchain in industry, governments and academia, one might tend to be inclined to think that blockchain has moved beyond a hype and a buzzword to something that is here to stay, somewhat analogous to cloud computing and Internet of Things (IoT) in their early days. While there are many (potential) applications of blockchain including in industrial IoT (IIoT), there are a number of ongoing challenges. In this special issue, we present existing state-of-the-art advances reported by the nine accepted papers. We then conclude the special issue with a number of potential research agenda.