Because of non-backward-compatible changes made in LISTSERV to the format of LISTSERV's SIGNUP files which allow UTF-8 characters to be used in passwords, and the addition of non-reversible subscriber password encryption, L-Soft STRONGLY RECOMMENDS that, prior to upgrading, a full backup be made of your LISTSERV installation if you are upgrading from a version earlier than 16.0.

IMPORTANT: Install your LISTSERV 17.5 product LAK before upgrading!


A valid product LAK (License Activation Key) with "REL=17.5" must be installed before upgrading or LISTSERV will not start after the upgrade.


If you have not received a LISTSERV 17.5 product LAK, please contact your sales representative or SALES@LSOFT.COM before upgrading!


If your product LAK has EXP=NEVER, you will also need to install an appropriate LISTSERV maintenance LAK.


To find out if you can upgrade to LISTSERV 17.5 with your current LAKs, please issue a SHOW LICENSE command to LISTSERV and examine the response. It will be similar to this:


License type:       Permanent

Expiration date:    None - perpetual license

Maintenance until:  31 Nov 2024, serial number MNT-XYZ-1;728996

Capacity:           Unlimited

Version:            17.5

Serial number:      XYZ-1

Build date:         20 Nov 2024


Your license key will be valid for the 17.5 upgrade if your current product LAK is for version 17.5 or higher and your maintenance is not expired.


If you are running the Free Edition, it will look like this:


* License type:      Graduated

* Expiration date:   None - perpetual license

* Maintenance until: 31 Dec 2024, serial number MNT-FREE-EDITION-WINNT-25;728996

* Capacity:          10 points (0 in use)

* Product options:   LITEFE

* Scope:             MAXSUB(500),PERLIST

* Version:           17.5

* Serial number:     FREE-EDITION-WINNT

* Build date:        20 Nov 2024

For the Free Edition, the license key will be valid for the 17.5 upgrade if your current product LAK is for version 17.5 or higher and your maintenance is the same as (or later than) the build date of the copy you are running.


Upgrading LISTSERV is almost as simple as installing it.  Simply follow these steps:

    • For paid copies of LISTSERV Lite: If you are upgrading from one full version of LISTSERV to another (for instance, from 17.0 to 17.5), you should have received a new LAK from your sales representative.  If you do not have a LAK for the version you are upgrading to, stop right here and contact your L-Soft sales representative. If you are not sure what version you are currently licensed for, send a "SHOW LICENSE" command to LISTSERV.
    • For the LISTSERV Lite Free Edition: Your installation kit will contain an updated LAK which permits you to continue running the Free Edition.
    • If you have received a new LAK, install it onto your old installation, following the instructions that come with the LAK (or see Section 2.3, above). Send LISTSERV a "SHOW LICENSE" command after restarting LISTSERV to ensure that the new LAK has been installed properly. Do not proceed further until this step has been correctly completed.
    • Back up the entire LISTSERV directory hierarchy (just in case).
    • Stop LISTSERV and SMTPL.
    • Get the current Windows evaluation kit from the LISTSERV evaluation kit download page and install it over your existing installation. Your current configuration, lists, and other settings will be preserved.  Note that evaluation kits are production code limited only by an evaluation LAK, which your production LAK will override.

Note:  If you have LISTSERV's web interface installed, the evaluation kit installer should upgrade WA.EXE and WA.SYM in your WWW_ARCHIVE_CGI directory.  If for any reason this does not happen, you can simply copy WA.EXE and WA.SYM from \LISTSERV\MAIN into the WWW_ARCHIVE_CGI directory to complete the web interface upgrade.
    • If you are running the legacy LSMTP MTA as your mailer, open the Windows Control Panel/Services applet and ensure that the "LISTSERV SMTP Listener" service is disabled.  This is very important!  Note that the current version of the installation GUI will not register SMTPL.EXE as a service if an installation of LSMTP is detected in the Windows registry, but it is still wise to check this.

Note:  L-Soft's legacy LSMTP mailer is no longer supported in any way.  While sites with valid licenses for L-Soft's legacy LSMTP mailer may of course continue to use LSMTP for both inbound and outbound mail, L-Soft strongly discourages the use of this discontinued, no longer supported product.  We will be happy to discuss alternatives with you; please simply write to support@lsoft.com and request details.  (If running LISTSERV Lite Free Edition, please write to LISTSERV-LITE@PEACH.EASE.LSOFT.COM instead.)
    • Restart LISTSERV and SMTPL (if not running legacy LSMTP) and send a command to make sure the installation was successful.