Debian 9 a.k.a. Stretch was now released about 3 years ago. The last version of Yunohost 2.7.x (released about 2 years ago) shipped a migration that allows to upgrade from Debian 8 a.ka. Jessie to Debian Stretch.
This topic is here to announce that we will start putting down all pieces of infrastructure related to Jessie / YunoHost 2.7.x (mainly .deb builds and install script) starting June 15th, 2020.
If you still are running YunoHost <= 2.7.x (we hope you do not, but unfortunately we’re also pretty sure some people do…), we can only encourage you to upgrade your server as soon as possible considering that we should start support for Debian 10 a.k.a. Buster in the coming weeks, and considering that the more you wait, the more complex your server upgrade will be (not to mention security risks).