Can't get SMTP to work with tls 1.2


We have a new policy which requires us to use tls v1.2 encryption when sending emails, and configuring SMTP with ‘tls’ doesn’t work. Kanboard is running on a Windows server and all was working well with ‘tls’ until now.

Can anyone tell us what we have to do to get Kanboard working with tls1.2?


Lets see what ChatGPT comes up with:

To use TLS v1.2 with Kanboard, you will need to make sure that the version of PHP you are using on your Windows server has support for TLS v1.2. In general, PHP versions 5.6.7 and higher have support for TLS v1.2.

You can check the version of PHP that you are using by running the following command in a command prompt:

php -v

If you are using a version of PHP that does not support TLS v1.2, you will need to upgrade to a newer version. You can usually do this by downloading the latest version of PHP from the official website and installing it on your server.

Once you have a version of PHP that supports TLS v1.2, you can configure Kanboard to use TLS v1.2 by editing the config.php file and setting the MAIL_SMTP_SECURE option to “tls”:

define('MAIL_SMTP_ENCRYPTION', 'tls');

This will enable Kanboard to use TLS v1.2 when sending emails. You may also need to update your SMTP server settings to use TLS v1.2, but this will depend on your specific setup.

I hope this helps! Let me know if you have any other questions.


Thanks! We will try this asap.

We are using PHP 8.0 so the problem wasn’t caused by an old version…
The SMTP server supports TLS1.2. When we send an email from the windows command line (TLS 1.2, without PHP) the mail is sent. It’s only emails from Kanboard that doesn’t work.

Any other ideas? Are we missing something else?

and you changed the config?
define('MAIL_SMTP_ENCRYPTION', 'tls');

Yes, ‘tls’ is configured. We must be missing something else. I’ll try from scratch with a new config file tomorrow.

No luck getting mail with tls 1.2 working with Kanboard on Windows server yet…
(Everything was working with tls 1.0)

Kanboard version: 1.2.20
PHP version: 8.2.0
OS version: Windows NT 10.0

try this.

constant is found here: