On October 21 at 8:00 AM PT, GOG announced that it would temporarily shut down its website and GOG Galaxy client services for maintenance, expected to last several hours. During the maintenance period, users were unable to access the GOG store and GOG Galaxy services normally.
GOG apologized for the inconvenience caused and thanked users for their patience. However, the company did not disclose the specific reason for this maintenance.
On the same day, a serious security vulnerability was exposed in PHP, the scripting language used for web development, prompting many websites and online services to go offline voluntarily to deploy security fixes. GOG's maintenance occurred after this security incident came to light, but there is currently no evidence proving a direct connection between the two, nor has GOG confirmed that this downtime was a preventive measure.
Other service disruptions or voluntary shutdowns also occurred on the same day, including the Finnish government shutting down some websites as a precaution, and players reporting that Final Fantasy XIV login servers were unavailable. However, existing information does not prove that these incidents are related to GOG's maintenance, and the cause of Final Fantasy XIV's outage has not been disclosed.