The new DLC for Fight Night Round 4 is coming on December 3rd. In addition to two new gameplay modes, there will be a significant (free) update to the core game. From EA:

Gameplay updates:

• Adjusted the locomotion speed at close proximity so that your opponent can no longer trap you with glued feet
• Increased the stamina cost when continually punching
• Increased stamina loss when continually weaving
• Increased stamina loss for users that spam upper body movement
• Can no longer perform a perfect block when spamming the block
• Increased the stamina cost when continually running away from your opponent
• No illegal blows can be thrown by either user when one user is in a stun state
• Increased stamina cost of Haymakers
• Tuned punch accuracy when opponents are moving their head
• Reduced locomotion speed when throwing punch combos

Create Player Updates

• Allow users to duplicate and edit ratings of licensed boxers

Online World Championship Updates

• Improved cheat detection logic

And finally, the details of the DLC timelines and pricing, per platform:

December 2

• X360 Gold & Silver – Title Update

December 3

• X360 Gold – Free Content – Accessories
• X360 Gold & Silver – Champions Pack (Boxers and Game Modes Available)
• PS3 – Title Update
• PS3 – Accessories and Champions Pack

December 10

• X360 Silver – Free Content – Accessories
• Pricing for Champions Pack
• Ring Rivalries – $1.99 US / 160 MS Points
• Old School Rules – $3.99 US / 320 MS Points
• Individual Boxers – $1.99 US / 160 MS Points (Evander Holyfield, Bernard Hopkins, Sonny Liston)
• Champions Pack Bundle – $9.99 US / 800 MS Points