[imp] imp link_attach_size_hard doesn't work

[Benedetto Vassallo]

Hi all
I have configured my imp installation (for test) witk this parameters:

$conf['compose']['use_vfs'] = true;
$conf['compose']['link_attachments'] = true;
$conf['compose']['link_attachments_notify'] = false;
$conf['compose']['link_attach_threshold'] = 4096;
$conf['compose']['link_attach_size_limit'] = 0;
$conf['compose']['link_attach_size_hard'] = 81920;
$conf['compose']['attach_size_limit'] = 0;
$conf['compose']['attach_count_limit'] = 0;

in order to get all attachment linked if the sum of them is bigger than 80K.
If I send an e-mail with an attachment smaller than 4K it is send ad  
normal attachment.
But if I send an e-mail whit an attachment bigger than 80K or with 2  
attachments (1 smaller than 4K and 1 bigger than 80K) I get an "error  
when communicating with the server" red rectangle  and in the log I  
get this error:

2021-03-08T10:26:09+00:00 EMERG: HORDE [imp] Call to a member function  
setRaw() on null [pid 12209 on line 2929 of  
"/var/www/horde5/imp/lib/Compose.php"]

Is there something wrong on my configuration or is an imp bug?
Best regards.
  --
Benedetto Vassallo
Responsabile U.O. Sviluppo e manutenzione dei sistemi
Sistema Informativo di Ateneo
Università degli studi di Palermo

Phone: +3909123860056
Fax:     +3909123860880