Broadsword Online Games have announced, this afternoon, that Publish 93 for Ultima Online has (or will soon have) gone live on all shards:

We are pleased to announce that Publish 93 will be available world wide this afternoon on all shards  at approximately 3 pm EDT May 31, 2016 . We will be taking down all shards between 11:30 and 12 PM EDT, please watch for a broadcast in game for shutdown.  Be sure to check out the full patch notes.    The new in-game “Ultima Store” will  be available after all shards have been published.  You can read all about the new Ultima Store here.

We want to thank everyone who provided feedback and helped test Publish 93.

One month game time codes should be available for purchase this afternoon or tomorrow on the game time store.

Accompanying the release of Publish 93 is a new piece of in-universe lore: Destiny & Decision, written (as usual) by EM Malachi. Much of the story concerns the Myrmidex; the Companion Geoffrey also features in it.

And, as noted in the quote above, details about the new in-game store can be found on the Ultima Online site, as well.

Item prices in the store are listed in Sovereigns. Your Sovereign balance is linked to your master account wallet; any of your characters on a particular shard tied to that wallet can access it. Your Sovereign balance can be viewed in the Ultima Store heading under the Help section accessible via the game client menu.