I have to send PDF e-mail attachments quite often, and sometimes they arrive with a different name and the ending .DAT instead of .pdf

The only relevant setting in main.inc.php is:
Code:
// Encoding of long/non-ascii attachment names:
// 0 - Full RFC 2231 compatible
// 1 - RFC 2047 for 'name' and RFC 2231 for 'filename' parameter (Thunderbird's default)
// 2 - Full 2047 compatible
$rcmail_config['mime_param_folding'] = 1;
I don't really know what that means, if that settings is responsible for the mentioned problem, and which setting is the most commonly used ("1" is the default of roundcube).

Any hint?