We recently launched Gmail Add-ons, which satisfy many of the same needs as Gmail contextual gadgets but also offer a better developer experience, cross-platform support, and more stability. We recommend that admins turn off their contextual gadgets and develop new or install existing Gmail Add-ons to serve their use cases. If Gmail contextual gadgets aren’t removed before August 1st, 2018, they’ll disappear automatically.
On August 1st, 2018, we’re planning to shut down all Gmail contextual gadgets. A Gmail contextual gadget is a gadget that is triggered by clues in Gmail, like the content of a subject line or an email message.