Ubisoft will be bringing down The Division's servers tomorrow morning, but the down time won't be for any game changing alterations or additions. Essentially, the server will be taken down tomorrow morning for your typical server maintenance.
According to Ubisoft, the maintenance will optimize servers and clean up databases. The maintenance will begin on Thursday, June 23 at 09:00 AM CEST / 03:00 AM EDT / 00:00 AM PDT and will be down for "approximately 2 hours."
This maintenance may bring hidden changes though. Later this month Xbox One owners will be the first to play the first piece of DLC for the Division, The Underground. This DLC is set to release on June 28th for Xbox One owners and a month later for PlayStation 4 and PC players.
The maintenance could very well be in preparation for the DLC, at least on the Xbox One… then again, I might just be wearing a tinfoil hat.