Infos zum Update von Dominik Schiener auf Slack:

@here, as a first step of the upgrade, the coordinator has already been turned on. We now release a new IRI version which will help the network to fully recover. The GUI release will be pushed out tomorrow (around 12:00CEST) and everything should go back to normal after that. *Keep in mind that the current GUI version is not compatible with this IRI release, as such don't try logging in to light wallet providers just yet.*
The blog post with further details on how to claim (for those affected) is currently being worked on and will be released together with the GUI tomorrow.