Don't worry! The Chrome version of Insomnia will be kept available for as long as necessary, but you should upgrade to the standalone version (3.0) as soon as possible.
Google announced today that they will be phasing out Chrome Apps by mid-2017. This means that the Chrome version (2.0) of Insomnia will become unavailable.
We will be removing support for packaged and hosted apps from Chrome on Windows, Mac, and Linux over the next two years.
To make sure that you are unaffected by this change, upgrade to the standalone version (3.0) today which is supported on Mac, Windows, and Linux platforms. After installation, export your data from 2.0 and import it into 3.0. Then, carry on with your work and enjoy the new features like cookie management, global environments, and code snippet generation.