Techno Kryon Concurrency means the collection of techniques and mechanisms that enable a system to perform several different tasks simultaneously. Concurrency is considered hard to understand. It helps to write powerful, fast execution, and reactive apps. In iOS we have NSOperation and Dispatch Queues to perform concurrency. · Utilize device hardware: Now all devices have a multi-core processor that allows developers to execute multiple processes in parallel. We should utilize this feature and get benefits out of the hardware. · Better user experience: While performing heavy tasks UI will freeze till the task execution. When the user faces this situation, the first step that user will take to uninstall/close your app without a second thought. With concurrency, all these tasks can be done in the background without changing the main thread or disturbing your users. They can still tap on buttons, scroll and navigate through your app, while it handles the