COBOL compiler versions, required runtimes, and support information

COBOL compilers by name and version

Table 1. COBOL compiler names, versions and releases, product identifiers, GA and EOS dates, and required runtimes
Compiler Version, release, and modification level Product identifier (PID) General availability (GA) date
(Year-Month-Day)
 End of support (EOS) date1
(Year-Month-Day)
 Required runtimes2
OS/VS COBOL 1.2.3 5740-CB1 1974-09-23 1999-12-31
  • OS/VS COBOL runtime library; or
  • VS COBOL II runtime library; or
  • z/OS Language Environment
OS/VS COBOL 1.2.4 5740-CB1 1976-09-23 1999-12-31
  • OS/VS COBOL runtime library; or
  • VS COBOL II runtime library; or
  • z/OS Language Environment
VS COBOL II 1.33 5668-958 1988-12-16 1996-06-30
  • VS COBOL II runtime library; or
  • z/OS Language Environment
VS COBOL II 1.43 5668-958 1993-03-12 2001-03-31
  • VS COBOL II runtime library; or
  • z/OS Language Environment
COBOL/370
 1.1 5688-197 1991-12-20 1997-09-30 z/OS Language Environment
COBOL for MVS & VM
 1.2 5688-197 1995-10-27 2001-12-31 z/OS Language Environment
COBOL for OS/390® & VM
 2.13 5648-A25 1997-05-23 2004-12-31 z/OS Language Environment
COBOL for OS/390 & VM
 2.23 5648-A25 2000-09-29 2004-12-31 z/OS Language Environment
Enterprise COBOL for z/OS®
 3.1 5655-G53 2001-11-30 2004-04-04 z/OS Language Environment
Enterprise COBOL for z/OS
 3.2 5655-G53 2002-09-27 2005-10-03 z/OS Language Environment
Enterprise COBOL for z/OS
 3.3 5655-G53 2004-02-27 2007-04-30 z/OS Language Environment
Enterprise COBOL for z/OS
 3.4 5655-G53 2005-07-01 2015-04-30 z/OS Language Environment
Enterprise COBOL for z/OS
 4.1 5655-S71 2007-12-14 2014-04-30 z/OS Language Environment
Enterprise COBOL for z/OS
 4.2 5655-S71 2009-08-28 2022-04-30 z/OS Language Environment
Enterprise COBOL for z/OS
 5.1 5655-W32 2013-06-21 2020-04-30 z/OS Language Environment
Enterprise COBOL for z/OS
 5.2 5655-W32 2015-02-27 2020-04-30 z/OS Language Environment
Enterprise COBOL Value Unit Edition for z/OS4
 5.2 5697-ECV 2015-10-06 2020-04-30 z/OS Language Environment
Enterprise COBOL for z/OS
 6.1 5655-EC6 2016-03-18 2022-09-30 z/OS Language Environment
Enterprise COBOL Value Unit Edition for z/OS4
 6.1 5697-V61 2016-03-18 2022-09-30 z/OS Language Environment
Enterprise COBOL for z/OS
 6.2 5655-EC6 2017-09-08 2024-09-30 z/OS Language Environment
Enterprise COBOL Value Unit Edition for z/OS4
 6.2 5697-V61 2017-09-08 2024-09-30 z/OS Language Environment
Enterprise COBOL for z/OS
 6.3 5655-EC6 2019-09-06 2025-09-30 z/OS Language Environment
Enterprise COBOL Value Unit Edition for z/OS4
 6.3 5697-V61 2019-09-06 2025-09-30 z/OS Language Environment
Enterprise COBOL for z/OS
 6.4 5655-EC6 2022-05-27 To be determined z/OS Language Environment
Enterprise COBOL Value Unit Edition for z/OS4
 6.4 5697-V61 2022-05-27 To be determined z/OS Language Environment
Notes:
  1. EOS stands for End of Support and refers to the last date on which IBM will deliver standard support services unless extensions or support upgrades are purchased. To check lifecycle details (lifecycle dates, announcement letters, and other information) for Enterprise COBOL for z/OS products, visit the COBOL for z/OS lifecycle website.
  2. For details about runtime components and their EOS dates, see Table 2.
  3. VS COBOL II 1.3 and 1.4, along with COBOL for OS/390 & VM 2.1 and 2.2, are all commonly referred to as COBOL 2. To ensure clear communication, it's important to specify the exact compiler version you are using when discussing migration, as the term COBOL 2 can be ambiguous.
  4. Enterprise COBOL Value Unit Edition for z/OS is the same as Enterprise COBOL for z/OS made available under a different product number and pricing metric.

Runtime libraries for COBOL programs

Every COBOL program requires runtime library routines to execute. Runtime libraries offer a variety of predefined functionalities, optimized for IBM Z hardware. Runtime libraries are sold either bundled with other products or as standalone products. In the latter case, runtime libraries are serviced by their own APARs and PTFs.

OS/VS COBOL and VS COBOL II runtime libraries were either bundled with the old compilers at purchase or needed to be purchased separately. In contrast, z/OS Language Environment is a base element exclusive to z/OS (existing only within z/OS) and does not need to be purchased separately. If you still use OS/VS COBOL and VS COBOL II runtime libraries, you are encouraged to move to z/OS Language Environment.

In addition to cost benefits, z/OS Language Environment provides a single language runtime library for COBOL, PL/I, C/C++, and FORTRAN. It supports existing applications and offers common condition handling, improved interlanguage communication (ILC), reusable libraries, and more efficient application development. Application development is simplified by the use of common conventions, common runtime facilities, and a set of shared callable services.

For details, see COBOL runtime options in the Enterprise COBOL Programming Guide and the z/OS Language Environment Vendor Interfaces.

Table 2. Runtime libraries for COBOL programs, product identifiers, components, and EOS dates
Runtime library Supported COBOL programs Product identifiers (PIDs) Component ID End of support (EOS) date
(Year-Month-Day)
OS/VS COBOL runtime library OS/VS COBOL
  • 5740-CB1 (compiler and library)
  • 5740-LM1 (library only)
  • 5740CB103
  • 5740LM103
 1999-12-31
VS COBOL II runtime library
  • OS/VS COBOL
  • VS COBOL II
  • 5668-958 (compiler, debugger, and library)
  • 5688-023 (compiler and library)
  • 5668-940 (library only)
  • 5688-022 (library only)
  • 566895801
  • 566894001
 2001-03-31
z/OS Language Environment
  • OS/VS COBOL2
  • VS COBOL II2
  • COBOL/370
  • COBOL for MVS & VM
  • COBOL for OS/390 & VM
  • Enterprise COBOL for z/OS 3.1 through 4.23
  • 5694-A01
  • 5650-ZOS
  • 5655-ZOS
  • 568819801 (Language Environment Common Execution Library)
  • 568819802 (Language Environment COBOL Library)1
 z/OS Language Environment is a component of z/OS and follows the lifecycle of z/OS4
Enterprise COBOL for z/OS 5.1 and later3
  • 5694-A01
  • 5650-ZOS
  • 5655-ZOS
  • 568819801 (Language Environment Common Execution Library)
  • 568819812 (Language Environment Enterprise COBOL Library)1
Notes:
  1. Component ID identifies each component in z/OS. For details, see Identifying modules, components, and products in z/OS MVS Diagnosis: Reference.
  2. With the older compilers OS/VS COBOL and VS COBOL II, there was an option to have the runtime routines statically linked to the load modules (the NORES compiler option) or dynamically accessed at run time (the RES compiler option). Since COBOL/370 1.1 in 1991, all COBOL compilers default to the RES behavior. If you want to link-edit those programs with z/OS Language Environment, see Moving to Language Environment.
  3. Different versions of Enterprise COBOL have different minimum release level requirements for z/OS Language Environment. For details, see Language Environment's runtime support for different compilers.
  4. Different z/OS versions and their releases have specific EOS dates. To check the EOS date for a specific z/OS release, visit the z/OS lifecycle website.

Support for COBOL programs after EOS

End of Support (EOS) refers to the last date on which IBM will deliver standard support services unless extensions or support upgrades are purchased. COBOL support has two aspects:
  • Support for the compiler: Support for compiling your program. Compilation is required after you make source code changes for new development or maintenance fixes. When COBOL compilers reach EOS, IBM discontinues support services for the compilers. However, COBOL programs generated by these compilers continue to run on the latest z/OS systems. Existing programs will continue to run on the latest z/OS systems without needing to be recompiled with a supported COBOL compiler. While you can continue using COBOL compilers that have reached EOS, IBM will not provide support services if you encounter any issues during the compilation of your programs.
  • Support for the runtime: Support for the execution of an existing COBOL program. If you encounter any issues during the execution of your programs, IBM will provide runtime support services for COBOL programs (including those generated from compilers that have reached EOS) that use a supported version of z/OS Language Environment as their runtime, as shown in Table 2.

Tools and information to assist your COBOL migration

In general, the migration process involves compiler migration (recompiling source programs with the Enterprise COBOL for z/OS compiler) and runtime migration (moving your applications to z/OS Language Environment®).

Basic information for compiler and runtime migration, and best practices

There are differences between older COBOL compilers and the Enterprise COBOL compilers that require you to upgrade your COBOL source programs. For example, COBOL 3 and later compilers require source code to be at the 85 COBOL Standard level or later. To aid in upgrading your COBOL programs, the COBOL 6 Migration Guide describes the language differences between older COBOL compilers and Enterprise COBOL and describes the IBM® conversion tools available to aid in converting your source programs to Enterprise COBOL programs. For details, see Conversion tools for source programs.

To aid in moving your runtime library to z/OS Language Environment, refer to Moving to Language Environment. For details about how to run existing VS COBOL II and OS/VS COBOL load modules under Language Environment, including link-edit requirements for support and recommended runtime options for compatible behavior, see Chapter 5. Running existing applications under Language Environment in the Enterprise COBOL 4.2 Compiler and Runtime Migration Guide.

One major migration challenge is the problems caused by invalid COBOL data, which cannot be detected by inspecting source code. You might get different results with COBOL 6 than with earlier compilers. To address this, you can go through a 2-compile and 2-test process with migration options. For details, see Upgrade recommendations and best practices.

The COBOL 6 Migration Guide also describes other differences that might require changes in your application development process in order to use Enterprise COBOL.

Additional resources and guidance to kickstart your COBOL migration
The following deliverables are also available to aid you in assessing the effort of moving from your older COBOL compiler to Enterprise COBOL:
  • IBM Enterprise COBOL for z/OS Migration Assistant.

    You can use the COBOL Migration Assistant to navigate through the compiler migration process from Enterprise COBOL 4 or earlier versions to Enterprise COBOL 6.

  • IBM Enterprise COBOL for z/OS Migration Portal.

    Check case studies, COBOL experts interview videos, the cloud-based COBOL Migration Assistant, no-charge COBOL Migration and Performance Tuning Webinars, FAQs, other IBM products to support your migration, and many other resources to help ease your migration efforts from Enterprise COBOL 4 or earlier versions to Enterprise COBOL 6.

Use IBM Automatic Binary Optimizer for z/OS (ABO) to reduce your COBOL migration scope and effort

IBM Automatic Binary Optimizer for z/OS (ABO) enables you to improve the performance of already compiled IBM COBOL programs without the need for recompilation. Using ABO 2.2 to optimize your COBOL 4.2 applications delivers comparable performance to applications compiled with COBOL 6.4.1 You can reduce the scope of COBOL migration by focusing on source code that is under active development. Use ABO to improve the performance of all other modules compiled with VS COBOL II 1.3 and later that do not have a recompilation plan.

To learn more about the relationship between COBOL and ABO, see Using ABO and Enterprise COBOL together in the IBM Automatic Binary Optimizer for z/OS User's Guide. To learn more about ABO, see the ABO product page.

1 DISCLAIMER: The performance improvements are based on the geometric mean of IBM internal measurements. Performance results for customer applications will vary, depending on the source code, the compiler options specified, and other factors.