Blizzard has been prepping us for the 1.0.4 patch, adding new features with each day that passes, and the word via their official blog is that the update is set to launch sometime today. In preparation for the patch, servers will be down throughout the day for maintenance purposes.
Servers are already going down in North America and should be back up and running by 1pm PST. European server maintenance will go from 8pm PST until 6am PST tomorrow and Asian server prep will start tomorrow at 11am PST until 11pm PST.
When all is said and down, the patch will push to users in a timely fashion. Keep in mind, until each region receives the patch, global play will not be an option. Luckily, with Blizzard's schedule, everyone should be back online and updated by 11pm on Wednesday.
The Paragon System will extend the game for players who have leveled their characters up to 60 and find themselves with little to do. Now, your character will have the ability to move up to Paragon level 100, a feat which might take you the rest of 2012. It also adjusts Magic Find, applying a 3% increase to a player each time they hit a new Paragon level.