The software updates to the iSeries are typically applied between 8a.m. and 1p.m. ET on Sunday mornings, although that can vary widely depending on the size of the release and other things that are happening at that same time (such as HA rollovers).

GOLD updates are deployed the business day prior to the iSeries host being updated.  For instance, if the host is being updated on Sunday morning, the GOLD update would be deployed on Friday.  Clients that do not utilize GUAPPLEs would be able to download the update package on Friday.  GUAPPLEs are configured to automatically update after-hours, and the GUAPPLE would automatically make the update available on Sunday morning after the host was updated.

There are times that updates are performed during the week.  In this scenario, the same rules apply - the iSeries host would be updated much earlier in the morning, well before any CU would open, and the GOLD update would be deployed the business day before.