​We’re in the process of upgrading the backend infrastructure that powers the EventStreams service.  When we switch EventStreams to the new​ infrastructure, the ‘offsets’ AKA Last-Event-IDs will change. 

Connected EventStreams SSE clients will reconnect and not be able to automatically consume from the exact position in the stream where they left off.  Instead, reconnecting clients will begin consuming from the latest messages in the stream.  This means that connected clients will likely miss any messages that occurred during the reconnect period.  Hopefully this will be a very small number of messages, as your SSE client should reconnect quickly.

This switch is scheduled to happen on June 5 2018, at around 17:30 UTC.

Let us know if you have any questions.

Thanks!

- Andrew Otto

  Senior Systems Engineer, WMF