TLS 1.0 and TLS 1.1 are about to be obsolete. This module warns clients

if they are using those versions, to prepare for disabling them.

# Configuration

``` {.lua}

modules_enabled = {

    -- other modules etc

    "warn_legacy_tls";

}

-- This is the default, you can leave it out if you don't wish to

-- customise or translate the message sent.

-- '%s' will be replaced with the TLS version in use.

legacy_tls_warning = [[

Your connection is encrypted using the %s protocol, which has been demonstrated to be insecure and will be disabled soon.  Please upgrade your client.

]]

```

## Options

`legacy_tls_warning`

:   A string. The text of the message sent to clients that use outdated

    TLS versions. Default as in the above example.

`legacy_tls_versions`

:   Set of TLS versions, defaults to

    `{ "SSLv3", "TLSv1", "TLSv1.1" }`{.lua}, i.e. TLS \< 1.2.