The eIDAS regulation came to life in 2014. Now it looks like decentralized identities (self-sovereign identities) for eIDs will follow. The idea is interesting: the user is in control of their identities. So far, however, self-sovereign identities has been a research topic and have hardly been tested in real-world. This raises the question which lessons leanred we can derive from eIDs. This is exactly what Michael Grabatin, Wolfgang Hommel and I did in our publication “eID and Self-Sovereign Identity Usage: An Overview“.