Download the WS-BPEL 2.0 specification here: http://www.oasis-open.org/committees/download.php/23730/wsbpel-v2.0-OS.pdf
A draft primer (http://www.oasis-open.org/committees/download.php/23797/wsbpel-primer-draft.doc) contains the following change summary:
3. What’s new in WS-BPEL 2.0
As a result of the OASIS Technical Committee’s issues process, the original BPEL4WS 1.1 specification has received several updates. The following list summarizes the major changes that have been incorporated in the WS-BPEL 2.0 specification.
Data Access
• Variables can now be declared using XML schema complex types
• XPath expressions are simplified by using the ‘$’ notation for variable access, for example, $myMsgVar.part1/po:poLine[@lineNo=3]
• Access to WSDL messages has been simplified by mapping directly mapping WSDL message parts to XML schema element/type variables
• Several clarifications have been added to the description of the <assign> activity’s <copy> semantics
• The keepSrcElementName option has been added to <copy> in order to support XSD substitution groups or choices
• The ignoreMissingFromData has been added to automatically some of <copy> operation, when the from data is missing.
• An extension operation has been added to the <assign> activity
• A standardized XSLT 1.0 function has been added to XPath expressions
• The ability to validate XML data has been added, both as an option of the <assign> activity and as a new <validate> activity
• Variable initialization as part the of variable declaration has been added
Scope Model
• New scope snapshot semantics have been defined
• Fault handling during compensation has been clarified
• The interaction between scope isolation and control links have been clarified
• Enrichment of fault catching model
• A <rethrow> activity has been added to fault handlers
• The <terminationHandler> has been added to scopes
• The exitOnStandardFault option has been added to processes and scopes
Message Operations
• The join option has been added to correlation sets in order to allow multiple participants to rendezvous at the same process with a deterministic order
• Partner link can now be declared local to a scope
• The initializePartnerRole option has been added to specify whether an endpoint reference must be bound to a partner link during deployment
• The messageExchange construct has been added to pair up concurrent <receive> and <reply> activities
New Activitiesy types
• Added serial and parallel <forEach> with optional completion condition
• Added <repeatUntil>
• Added new extension activity
• Changed <switch> to <if>-<elseif>-<else>
• Changed <terminate> to <exit>
• Differentiate different cases of <compensate> by renaming them to <compensate> and <compensateScope>
Miscellaneous Cchanges
• Added repeatEvery alarm feature to event handlers
• Clarified resources resolution (e.g. variable, partner link) for event handlers
• Added formal <documentation> support
• Added extension namespace declarations in order to specify what extension must be understood
• Add <import> support to import WSDL and XSD formally
Abstract Processes
• Clarified Abstract Process usage patterns
• Introduced Abstract Profiles to address different needs in Abstract Processes, and two concrete profiles “Observable Behavior” and “Process Template” listed in the specification