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Migration considerations for Version 8.0 or later on Windows

From Version 8.0, a number of changes were made for IBM MQ for Windows. We must understand these changes before planning any migration tasks for Version 8.0 or later on Windows.


Installing a single copy of the product

If we have an existing previous version of the product on the system, and want to upgrade to the latest version, you have various options. We can either:

  • Uninstall the previous version and then install the latest version,
  • Install the new copy alongside the currently installed one and uninstall the original at a later time. See Installing the product alongside an existing version, or
  • Perform a migration installation, electing to replace the currently installed version when prompted.

After you have installed the product, start each queue manager and its data migration takes place. This includes the migration of queue managers from 32-bit to 64-bit.


Installing the product alongside an existing version

To install another version of the product alongside your existing product we can do so. See Multiple IBM MQ installations and Migrating on Windows: side-by-side for further information.

When you install the new version of the product, run the setmqm command to associate the queue managers with the new installation.

Start each queue manager in turn and its data migration takes place.


Upgrading one of a pair of (or more) installations

If you already have, for example, an IBM MQ Version 8.0 installation and an IBM MQ Version 9.0 installation on a machine, upgrading the Version 8.0 installation to Version 9.0 requires the following additional step.

When you start the Version 9.0 installer, we are asked whether we want to Install a new instance or Maintain or upgrade an existing instance.

However, only the other Version 9.0 installation, or installations, are displayed; not the Version 8.0 installation in the selection box. At this point, select Install a new instance.

After the splash screen has been displayed, a second panel appears, which lists any older installations that we can upgrade to Version 9.0 using the Version 9.0 installer.

On this panel, select Upgrade 8.0.0.n Installation 'Installation m', and then click Next.


Change of digital signature algorithm

The IBM MQ programs and installation image are digitally signed on Windows to confirm that they are genuine and unmodified.

In older releases before IBM MQ Version 8.0, the product was signed using the SHA-1 with RSA algorithm.

From Version 8.0, the SHA-256 with RSA algorithm is used. Some older versions of Windows do not support the new digital signature algorithm, but those versions are not supported by IBM MQ Version 8.0 or later.

See Hardware and software requirements on Windows systems, and ensure that you install IBM MQ Version 8.0 or later on a supported version of Windows.


Existing applications

All applications that were built with previous versions of the product continue to work in Version 8.0 or later with a 64 bit queue manager.

All applications using the C++ object interface need to be rebuilt; applications using the C interface are not affected.


Exits

Queue manager exits on Windows 64-bit operating systems must be compiled as 64-bit exits. Any 32-bit queue manager exits must be recompiled before they can be used with a 64-bit queue manager. If you try to use a 32-bit exit with a 64-bit queue manager on IBM MQ Version 8.0 or later, an AMQ9535 "invalid exit" error message is issued.


Clients

32-bit client applications can connect transparently to queue managers from all supported versions of the product. This includes 64-bit IBM MQ Version 8.0 or later.


Samples

From IBM MQ Version 8.0, the samples for the C and C++ languages are compiled as 64-bit.

Parent topic: Plan to migrate IBM MQ to a later version on Windows


Related information

Last updated: 2020-10-04