Last Epoch’s online servers will become unavailable on September 30, a full 24 hours before Season 5 launches on October 1 at 11 AM CDT. Eleventh Hour Games confirms the interruption in its Season 5 patch notes.

That 24-hour notice puts the planned maintenance start at 11 AM CDT on September 30, or 4 PM UTC. The scheduled October 1 launch uses the same time. Finish any final online sessions before the September 30 shutdown.

Official Last Epoch diagram showing five base classes and their Masteries
Official Last Epoch class artwork. True Offline remains available during the planned online interruption.Eleventh Hour Games

True Offline mode will remain available during maintenance. The developer directs players to Steam’s launch settings to access it, so select that mode when starting the game if you want to play during the online outage.

The notice does not give an earlier online reopening time. Plan around the October 1 launch, and check that service has returned before organizing an online session. The stated offline option remains available during the planned interruption.