A WebClient application can support 32-bit, 64-bit, or both 32-bit and 64-bit. If you define an application for a particular platform, it indicates that the application must be run with a WebClient version for that platform only.

If you define an application as a 32-bit application, it will run only with 32-bit WebClient, or if you define an application as a 64-bit application, it will run only with 64-bit WebClient.

When installing 32-bit WebClient applications on a 64-bit Windows platform, the applications are by default installed in the same file system and registry where other 32-bit applications are stored. 64-bit WebClient applications are by default in the file system and registry where other 64-bit applications are stored.

Applications that are defined to support both 32-bit and 64-bit can run on either 32-bit or 64-bit versions of WebClient. It lets you support both platforms within a single WebClient application with a single set of deployment files and you do not need separate versions of the same application.

Applications that support both 32-bit and 64-bit have special handling. Consider the following:

  • If the application is new, the WebClient platform required must match the Windows platform, for example, if installed on 32-bit Windows, 32-bit WebClient is required and if installed on 64-bit Windows, 64-bit WebClient is required. This allows a vendor to support both platforms with a single application and relieves the end-user of the decision of whether they should run 32-bit WebClient or 64-bit WebClient.
  • If you have an existing 32-bit application, you can define the application for both 32-bit and 64-bit. The existing end-users of the application must manually migrate to the new platforms. End-users with 64-bit Windows running older versions of the application will have been running a 32-bit application with 32-bit WebClient. You can define how the end-users can move to 64-bit WebClient in the following ways:
    • Making it mandatory that the end-user to upgrade to 64-bit WebClient
    • Asking the end-user if they wish to use 64-bit WebClient
    • Continuing to use 32-bit WebClient
Note: Location of 32-bit and 64-bit applications is different as per 64-bit Windows standards, if you want to upgrade to 64-bit WebClient, you must uninstall the older version of the 32-bit application and install the application as 64-bit.
The WebClient Initializer (prowcini.exe) detects whether the packaged application supports both 32-bit and 64-bit platforms, or just one of them. The following pseudocode explains its operation:
if prowcapc format not supported by prowcini
  upgrade to newer webclient version
else
  if app already installed for the available platform(s)
    if win64 and prowcapc is 32-bit and 64-bit
      if installed app is 32-bit
        if (force uninstall) or (ask uninstall)
          uninstall and reinstall
        else /* continue as 32-bit */
          run/upgrade as normal
      else /* installed app is 64-bit */
        run/upgrade as normal
    else /* app is installed for this platform */
      run/upgrade as normal
  else if app is installed for wrong platform
    uninstall and reinstall
  else if 64-bit app and win32
    error, cannot install
  else /* new app */
    install app