Apt-get update : Erreur de GPG : NO_PUBKEY 4ABE1AC7557BEFF9



Steps to reproduce
1. apt-get update

Actual behaviour
W: Erreur de GPG : http://download.opensuse.org Release : Les signatures suivantes n'ont pas pu être vérifiées car la clé publique n'est pas disponible : NO_PUBKEY 4ABE1AC7557BEFF9

Server configuration
Operating system: Debian Jessie
Database: mysql version 14.14
PHP version: 5.6.24
ownCloud version (see ownCloud admin page): 8.1.9


It helps to read the whole install instructions and import the missing pub key.


That's not a new install.
My owncloud is in production, i am just trying to update owncloud like i did since i'd install it.
I've never had this pub key before.


Keys changed as announced at various places like: