VMware has released the latest update to its ESX(i) 3.5 flagship product, Update 4.  It is strongly recommended that you upgrade to VMware vCenter 2.5 Update 4 prior to upgrading your ESX hosts.  Updates such as this one typically include a number of system improvements and also all of the patches available in-between it and the previous update available. Numerous driver additions and updates have been added to this update roll-up, including;

• Expanded Support for Enhanced vmxnet Adapter
• Enablement of Intel Xeon Processor 5500 Series
• QLogic Fibre Channel Adapter Driver Update
• Emulex Fibre Channel Adapter Driver Update
• LSI megaraid_sas and mptscsi Storage Controller Driver Update
• Newly Supported Guest Operating Systems
  • SUSE Linux Enterprise Server 11
  • SUSE Linux Enterprise Desktop 11
  • Ubuntu 8.10 Desktop and Server Editions
  • Windows Preinstallation Environment 2.0
• Newly Supported Management Agents
• Newly Supported I/O Devices
  • SAS Controllers and SATA Controllers
    • PMC 8011 (for SAS and SATA drives)
    • Intel ICH9
    • Intel ICH10
    • CERC 6/I SATA/SAS Integrated RAID Controller (for SAS and SATA drivers)
    • HP Smart Array P700m Controller
  • Network Cards
    • HP NC375i Integrated Quad Port Multifunction Gigabit Server Adapter
    • HP NC362i Integrated Dual port Gigabit Server Adapter
    • Intel 82598EB 10 Gigabit AT Network Connection
    • HP NC360m Dual 1 Gigabit/NC364m Quad 1 Gigabit
    • Intel Gigabit CT Desktop Adapter
    • Intel 82574L Gigabit Network Connection
    • Intel 10 Gigabit XF SR Dual Port Server Adapter
    • Intel 10 Gigabit XF SR Server Adapter
    • Intel 10 Gigabit XF LR Server Adapter
    • Intel 10 Gigabit CX4 Dual Port Server Adapter
    • Intel 10 Gigabit AF DA Dual Port Server Adapter
    • Intel 10 Gigabit AT Server Adapter
    • Intel 82598EB 10 Gigabit AT CX4 Network Connection
    • NetXtreme BCM5722 Gigabit Ethernet
    • NetXtreme BCM5755 Gigabit Ethernet
    • NetXtreme BCM5755M Gigabit Ethernet
    • NetXtreme BCM5756 Gigabit Ethernet
  • Onboard Management Processors
    • IBM system management processor (iBMC)
  • Storage Arrays
    • SUN StorageTek 2530 SAS Array
    • Sun Storage 6580 Array
    • Sun Storage 6780 Array

 I wanted to just give you a high-level overview of the updates in this release, all of the gory details can be found in the full release notes.