IBM announced WebSphere Version 5 in May but delayed the release after tentative feedback from customers.
Many customers said they were still getting used to Version 3.5 and were unlikely to upgrade because of the effort required to move mission-critical applications to a new platform.
"Customers are still trying to digest the last release," affirmed Susan Aldrich, an analyst at Patricia Seybold Group. "They're not in a hurry for more releases sooner."
Analysts said WebSphere Version 5 would bring IBM up to par in terms of J2EE and Web services support with BEA Systems' WebLogic 7.0, which shipped in late June. IBM and BEA are the market leaders in the application server market.
But Stefan Van Overtveldt, program director of WebSphere technical marketing, said IBM not only complies with J2EE 1.3, but also supports a majority of the J2EE 1.4 features that are due to be finalised next year. He said IBM also built in support for Web services technologies that it donated to the open-source community.
Explaining the WebSphere delay, Van Overtveldt said top customers told IBM that they wanted to get the WebSphere Studio developer tool, which was due for release in November, prior to the application server.
IBM therefore flipped the product schedules and worked to finish the tool first, which is integrated to work with the application server.
"The delay really only matters to the most cutting edge of developers, and that's [IBM's independent software vendor] partners," said Josh Walker, an analyst at Forrester Research.
Walker said IT shops had been crying out for improved tools to deploy application servers. He said major application server vendors had reached a level of parity "where there's no longer this feature/function race".
Meta Group analyst Thomas Murphy said users of older versions of WebSphere would be lured to WebSphere 5 by the new WebSphere Studio development environment.
Other features in WebSphere 5 include support for new autonomic computing technologies that aim to help companies lower the cost of administration and improve application response time.
Van Overtveldt said the server offered self-configuring to move from a single-server environment to a clustered environment, automatic tuning to support specific applications, and predictive failure analysis to prevent or fix problems. The server can also prioritise requests from preferred customers
WebSphere 5 also offers enhanced support for Web services. IBM included two new technologies that it turned over to the open-source community: Web Services Invocation Framework, which allows Web services to be invoked and developed across a variety of network and transport protocols, and Axis 3.0, a high-speed parser of Simple Object Access Protocol requests.
IBM also built in a Web Services Gateway to allow companies to take internal Web services applications and publish them securely on the Internet, a private Universal Description, Discovery and Integration repository and a proprietary Flow Definition Markup Language (FDML) to allow users to draw workflows visually.
Van Overtveldt said FDML was a subset of the Business Process Execution Language for Web Services, which was announced in August by IBM, BEA and Microsoft.
WebSphere pricing starts at $8,000 (£5,174) for a single-server configuration and $12,000 with support for network features such as clustering and failover.