Request is very broad, what version of code are you looking to upgrade to ? looking for specific features not found in your current code? anything not working properly? or is it simply you wan to upgrade to latest ASA code? in any case, you can always reference this link which provides detail information on features added , fixes, or opened caveats and upgrade requirements on every code for the ASA and ASDM, latest code is marked as ( New) for both ASA code and ASDM code.
Cisco ASA 5500 Series Adaptive Security Appliance, and Cisco Adaptive Security Device Manager
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...