THE CRUNCH
GOG announced on 21 October that its store and GOG Galaxy launcher would be offline for a couple of hours of maintenance, as a number of major websites and services went offline to apply fixes for critical vulnerabilities in PHP, the scripting language widely used to build web services. GOG's announcement did not state a cause, and the article notes it is not hard to speculate about the timing. Numerous other outages were reported the same morning as security teams applied fixes.
The outages extended well beyond games. The government of Finland took down its websites as a precaution, and players reported that Final Fantasy 14 login servers were down. GOG's message apologised for the inconvenience and asked for patience while the maintenance ran.