Attachments not synced (Outlook 2010)


our customer uses Outlook 2010 and has the following problem (v1 and also with new V2):

when archiving emails the attachments are not saved to CRM.

The option is activated in the settings.

I tried to make some debug-Logs in rest.php and saw the following calls:

set_entry (on Emails)
set_entry (on Emails)
set_relationship (to Contacts)

So no call to set_entry (for Notes) and set_note_attachment

now we also installed the Plugin on our internal Developementcomputers (NOT the Environment of our customer).
We internally use Outlook 2016. With our internal system the archiving of attachments work fine.

the rest.php log looks like:

set_entry (Emails)
set_entry (Notes)

So my mainquestion: should the plugin work correctly in Outlook 2010 or are there known problems with saving Attachments while archiving?