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 removed. 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".