Upgrading Stunnel to the Latest Version

DO NOT UPGRADE STUNNEL until you have been contacted by Vital Soft or Fiserv.

Prepare for Stunnel Upgrade

• Please note that installation does require a reboot of your PC / workstation.
• Save copies of the following 3 files - you will need them later in the upgrade process.

C:\Program Files\stunnel\certs.pem
C:\Program Files\stunnel\stunnel.pem
C:\Program Files\stunnel\stunnel.conf

• Download the latest version of stunnel here.

Uninstall the Previous Version of Stunnel

• Stop the Stunnel service

Run the Windows Services program, locate the stunnel service and click Stop.

• Uninstall the currently installed version (5.01) of stunnel by running the following program.

C:\Program Files\stunnel\uninstall.exe

• Verify that the C:\Program Files\stunnel directory was deleted. If it remains, use File Manager to delete it.

Install Stunnel

• Install the most recent version of stunnel (5.75 in June 2025.)
  • Choose the options that are appropriate for your organization.
  • By default, stunnel will be installed in C:\Program Files (x86)\
  • During installation you will be asked questions to create a default certificate. This certificate will not be used, so you can enter whatever values you choose or just press Enter on all of the prompts.
  • Do NOT run stunnel at the end of installation.

Complete the Installation

• Copy the three saved files from step 1 (certs.pem, stunnel.pem and stunnel.conf) into the following directory:

C:\Program Files (x86)\stunnel\conf

• Install the stunnel service using Powershell. If you installed stunnel for all users on the computer, you may need to run Powershell as the Administrator.

When Windows Powershell is running, enter the following commands:

cd C:\Program Files (x86)\stunnel\bin
./stunnel -uninstall
./stunnel -install

• Reboot your PC.

Verifying the Installation

• Run Windows Services and verify that the stunnel service is running. The service is now called "Stunnel TLS Wrapper".