The modernisation of Thunderbird’s user interface is a fact. Thunderbird 57 is now following Mozilla’s Photon design, and there is also a new theme available based on the design by the Monterail team. In April 2017 Thunderbird released its successful Extended Service Release (ESR) version 52. This release has just seen it’s fifth “dot update” 52.5.0, where fixes, stability and minor functionality improvements were shipped. Thunderbird 57 beta was also very successful. While Thunderbird 58 is equally stable and offers further cutting-edge improvements to Thunderbird users, the user community is starting to feel the impact of Mozilla platform changes which are phasing out so-called legacy add-ons. The Thunderbird technical leadership is working closely with add-on authors who face the challenge of updating their add-ons to work with the Mozilla interface changes. With a few usually simple changes most add-ons can be made to work in Thunderbird 58 beta.