SHARE is releasing a new article that brings together the perspectives of Independent Software Vendors (ISVs) on IBM’s decision to sunset zPDT, the on‑premise z/OS emulation environment that many rely on for development and testing. The article summarizes the concerns raised by ISVs and reflects the information that was available when the change was first announced.

As SHARE gathered input and prepared the draft, IBM leadership reached out after reviewing the material and invited SHARE to discuss the topic further. SHARE President Art Gutowski and board member Frank Chu, a developer with Izzi Software, met with Meredith Stowell, Vice President of Ecosystem at IBM, and Rosalind Radcliffe, CTO for the IBM Z Ecosystem.

In that conversation, IBM acknowledged that aspects of the communication around the decision could have been clearer and noted that there are legal, contractual, and compliance constraints that limit the details they can share. They explained that IBM’s decision was motivated by the need to move toward an alternative with stronger performance, improved security, and a more streamlined experience, particularly for solutions intended for mission‑critical environments. IBM also emphasized their commitment to promoting higher levels of readiness and resilience in software that ultimately runs on clients’ production systems.

Following the announcement, IBM has actively engaged ISVs through extensive one-on-one conversations to address questions, concerns, and potential pathway options. IBM has been acting on the feedback received and confirmed that an on‑premise replacement solution for ISVs is currently in development. While details, such as timing and pricing, are not yet available, IBM is inviting sponsor users to participate in early testing and provide input throughout the process. ISVs interested in becoming sponsor users or sharing feedback are encouraged to contact IBM’s zOPD Program Office via email at zOPD@ibm.com.

SHARE remains committed to representing the mainframe community and facilitating constructive conversations across the ecosystem. This dialogue reflects the value of collective advocacy and SHARE’s ongoing role in bringing together ISVs, clients, and IBM to support the future of the platform.

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SHARE Position Paper on the Withdrawal of zPDT

Issued on behalf of the SHARE membership with the support of the Board of Directors
In Support of the IBM Z Independent Software Vendor Community

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Introduction

IBM’s decision to withdraw zPDT and transition to new development access models has significant implications for the IBM Z ecosystem, particularly for smaller companies that drive innovation and solution diversity. SHARE believes that a vibrant, diverse vendor community is essential to sustaining a healthy marketplace that benefits IBM’s customers and the broader industry. The IBM Z platform remains a cornerstone for mission-critical systems worldwide, and its importance continues to grow as organizations demand secure, high-capacity solutions to protect their most valuable information.

This moment presents an opportunity to strengthen the ecosystem and embrace innovation from all participants, including smaller providers. SHARE deeply values IBM’s leadership and contributions and is committed to working collaboratively with IBM and the entire community to develop solutions that support ecosystem vitality. This paper reflects the position of SHARE.

1. Purpose and Scope

This document represents SHARE's position regarding IBM’s withdrawal of the z Systems Personal Development Tool (zPDT) and the transition to new development access models.

The purpose of this paper is to:

• Communicate the concerns raised by the SHARE community, especially Independent Software Vendors (ISVs).
• Document the operational and strategic risks associated with the discontinuation of zPDT.
• Address the severely damaged dialogue and collaborative planning between IBM and ecosystem stakeholders.
• Advocate for interim and alternative solutions to prevent disruption to the IBM Z platform ecosystem.

While one contributor to this document is also an affected ISV, this position reflects collective feedback gathered through community discussion, not individual commercial interest.

2. Background: The Role of zPDT

Since October 2009, zPDT has provided a practical, cost-effective, and locally controlled development environment for:

• ISVs developing essential IBM Z software
• Partners and tooling vendors requiring sysplex testing, systems-level development, automation, middleware, or debugging capabilities

zPDT has played a foundational role in enabling participation in the IBM Z software ecosystem by organizations without direct access to physical IBM Z hardware.

3. Concerns With the Withdrawal Process

3.1 Lack of Advance Notice

Many ISVs and development organizations — including IBM’s authorized zPDT distributor — learned of the withdrawal at the time of public announcement. The absence of phased communication or early notice has created:

• Contractual and budgeting uncertainty
• Operational planning disruption
• Risk to ongoing customer support commitments

3.2 Absence of Broad Stakeholder Consultation

Based on community feedback, there was no broad engagement with groups traditionally involved in decisions affecting the IBM Z ecosystem, including:

• SHARE technical committees
• ISV partners
• Enterprise users or regulated industry adopters

The abrupt announcement of zPDT withdrawal, coupled with inconsistent follow-up messaging, has damaged the community’s trust in IBM’s direction regarding ecosystem access to z/OS. In the absence of clear and consistent rationale, stakeholders have drawn divergent conclusions — ranging from concerns that IBM intends to more tightly control ISV access to a view that the change was executed with insufficient planning, despite IBM providing alternatives. IBM had a clear opportunity to minimize this impact by using its semiannual Technical Disclosure Meetings to announce the change earlier and present a stable, credible path forward. This experience underscores why early engagement and collaboration matter. SHARE recognizes IBM’s decision-making authority but notes that collaboration has historically strengthened platform outcomes.

4. Community Feedback and Documented Challenges

Extensive discussion has taken place in the public zPDT Groups.io community, which represents diverse technical roles, including ISVs,  systems programmers, and tooling vendors.

Common themes include:

• Concerns regarding loss of capabilities critical to development workflows
• Lack of clarity on technical limitations and data governance
• Difficulty aligning new offerings with existing release support obligations and customer expectations

These perspectives represent systemic impact rather than isolated cases.

5. Challenges ISVs Face Under the New Development Access Models

Feedback indicates that several factors may pose barriers to widespread adoption:

• Security and IP stewardship
  ISVs require confidence in access boundaries, enforcement controls, and long-term protection of proprietary code and data.
• Jurisdictional constraints
  Organizations operating in regions with strict data residency requirements may not be able to adopt U.S.-hosted environments.
• Cost predictability
  Some models introduce variable usage-based billing that complicates budgeting and scaling.
  • Member perspective (SHARE member; ISV): “I expect my development cost will at least triple if I have to rely solely on the RDP offering.”
• Workflow disruption
  Many existing CI/CD, automation, and debugging workflows assume full administrative access to a local environment.
  • Member perspective (John Gates, SHARE member): “Asking us to create an environment from scratch that will do what zPDT is doing for us today is not only extraordinarily difficult, it’s simply not reasonable for IBM to ask us to do it for free.”
• Performance considerations
  Latency-sensitive development and iterative test cycles may be affected in remote environments.

6. IBM’s Proposed Successor Models to zPDT

IBM has identified two offerings expected to serve as successors to zPDT. Both reflect continued IBM investment in providing development environments for the community. However, user feedback indicates that further alignment may be needed before they can serve as full replacements.

6.1 Hosted Development for ISVs (HDISV)

HDISV is a cloud-hosted z/OS environment provided in tiered subscription models. Early community input highlights the following considerations:

• Hosted environments are initially available only in U.S. regions, which may limit adoption by organizations with sovereignty requirements.
• Some ISVs have requested more explicit guidance regarding the security model, especially regarding proprietary source code and environmental access boundaries.
• Only the most current GA release of z/OS is available; earlier releases needed for customer support are not included.
• Initial storage allocation (50 GB) may be insufficient for multi-developer workflows, large regression suites, and test data requirements, with expansion options not yet available.
• Some ISVs report that HDISV is not yet operationally usable as a near-term replacement due to missing baseline capabilities needed for always-on development and test workflows.
• John Gates (SHARE member): “HDISV is not a fully functional, well-thought-out solution. It is missing basic capability that will not allow us to use it.”
• ISVs also report that limited near-term technical detail and roadmap transparency make it difficult to plan migrations within the announced transition window.
• z/VSE is not supported.

6.2 z Remote Development Program (zRDP)

zRDP provides access to IBM-managed physical hardware under virtualization. User feedback indicates:

• As with HDISV, clarity around data handling, security controls, and jurisdiction compliance remains a priority.
• Several ISVs report that the work-unit pricing model can be multiples of a comparably equipped zPDT for sustained use, which may make zRDP cost-prohibitive as a long-term replacement.
• John Gates (SHARE member): “Starting at roughly 3X the cost of a comparably equipped zPDT and rising quickly after that, it’s just not a solution we could consider for sustained usage.”
• Only current GA releases of z/OS are supported.
• Default storage allocation (10 GB) may require incremental upgrades for realistic development and test environments.
• Some features, such as sysplex support, may require additional cost.

6.3 Alignment and Gaps Relative to zPDT

Both HDISV and zRDP represent structured offerings with potential. For well-established ISVs with existing local automation, back-level support obligations, and complex test environments, the current offerings pose significant challenges and, in some cases, result in regressions in capability.

At the same time, these offerings may be compelling as an on-ramp for start-ups, academic programs, and organizations seeking an initial, lower-friction entry point into the IBM Z ecosystem—provided that data sovereignty, residency, and intellectual property protection requirements can be clearly met.

In their present form, however, neither HDISV nor zRDP fully replaces several key characteristics of zPDT, including:

John Gates (SHARE member): “Quite simply, neither zRDP nor HDISV is usable as a replacement for the always-on, always-available aspects of zPDT.”

• Ability to run multiple or back-level z/OS releases
• On-premises autonomy and offline administrative control
• Flexibility for system-level work, test automation, and archival retention
• Guarantee absolute security of proprietary ISV intellectual property — due diligence prevents a business from placing sensitive data in a competitor's cloud

SHARE recommends continued iteration, pilot opportunities, and open dialogue to ensure that successor environments support the full diversity of IBM Z ISV requirements.

7. Potential Impacts to the IBM Z Ecosystem

If successor models cannot meet current development needs, potential consequences include:

• Some ISVs report they are evaluating whether to reduce investment in, increase prices for, or discontinue IBM Z offerings if successor access models cannot meet availability, capability, and cost requirements — potentially impacting regulated-industry customers.
• John Gates (SHARE member): “I have been asked on multiple occasions by my executives whether we can continue to trust IBM’s commitment to the platform and the ISV community. Quite frankly, I have no good answer for them.”
• Reduced ISV participation and product diversity
• Potentially higher software costs for customers
• Risks to the pace of innovation and modernization tooling, especially for smaller providers

A healthy and diverse vendor ecosystem is essential to platform vitality. The IBM Z platform would not exist without IBM’s long-term investment and stewardship, but the breadth and depth of ISV participation drive its day-to-day relevance and innovation. Policies or access models that unintentionally create barriers for ISVs ultimately risk harming not only those vendors but also IBM customers and IBM itself over the long term.

• Improves User Choice and Satisfaction: A wider array of choices allows the platform to cater to a broader spectrum of user needs, preferences, and price points. This personalization capability is a major driver of user satisfaction and loyalty.
• Fosters a Network Effect: A strong and active vendor community attracts more users, and a large user base, in turn, attracts more vendors. This positive feedback loop, or network effect, significantly increases the platform's overall value and market dominance.

7.1 Strategic and Perception-Related Considerations

As IBM Z tools and solutions become increasingly interconnected, the ability for vendors to test and validate integrated workflows is essential for delivering cohesive user experiences. Restrictions that limit cross-vendor interoperability may slow innovation and reinforce outdated perceptions of the platform as less open than modern enterprise environments.

In addition, the long-term strength of IBM Z relies on a shared sense of good-faith collaboration among IBM, customers, and the broader vendor community. Ensuring transparency and predictability in decisions that influence development access helps maintain confidence in the platform’s direction and avoids setting precedents that may be viewed as restrictive or unilateral.

8. Recommendations and Requested Actions

SHARE respectfully requests that IBM:

• Extend transition timelines to allow for planning and evaluation.
• Provide a locally controlled development option with a compliance-oriented revocation mechanism (for example, a token/license approach that allows timely termination when needed while preserving predictable access for compliant ISVs).
• Member suggestion (SHARE member; ISV): Consider a centrally managed license service (building on existing IBM licensing patterns) that supports timely revocation when needed while preserving a local development workflow for compliant ISVs.
• Consider allowing qualified third-party vendors to provide z/OS hosting services for ISV development and test under IBM-approved terms and conditions, with cost to ISVs broadly comparable to the prior zPDT-based development experience, as an alternative to HDISV and zRDP.
• Establish a joint advisory working group including SHARE, ISVs, and IBM stakeholders.
• Support multiple access models that reflect different technical and regulatory requirements.
• Publish clear technical and pricing roadmaps to facilitate long-term planning.
• Provide a unified and transparent articulation of intent, strategic direction, and expected outcomes. This will help with long-term planning and building support for alternative solutions.

Closing Statement

SHARE acknowledges IBM’s longstanding stewardship of the platform and the complexity inherent in evolving development of access models. We believe that collaborative refinement of these offerings will help ensure continuity, innovation, and a healthy ISV ecosystem.

Since the announcement, several differing rationales have circulated, including modernization goals, simplification of development environments, and alleged concerns regarding licensing compliance. No consistent official public rationale has been provided.

This is a pivotal moment for the IBM Z community: decisions made now will shape the platform's future and its ability to meet growing demands for security, scalability, and resilience. SHARE stands ready to partner with IBM and all stakeholders to co-create solutions that preserve ecosystem diversity, foster innovation, and deliver maximum value to IBM’s customers.