Error in combination with z-push/ Kopano with attachment-names in Outlook

[Christian Still]

Error only happens with the packages from ubuntu repos,
when installing the nightly-packages from Kopano-Community,
with their own libvmime-Package, it works fine. (libvmime-kopano1)

The problem shows up, when using Kopano from repos with z-push,
to connect Win Outlook over ActiveSync.
When receiving a mail in this setup, from another Outlook sender with more than one attachment,
all attachments show up as Unnamed Attachment.X (Unbenannte Anlage.X)
It seems possible to me, that this only applys to german users, because of all forum posts faceing this issue, are german users.

Through some Kopano-dev forum posts, i came to the suspicion, that it could be related to the vmime package.

If you need any further information, please let me know, i would be happy if i could help.

Description: Ubuntu 18.04.2 LTS
Release: 18.04
libvmime1:amd64 0.9.2-5build2 amd64 C++ mail library (runtime library)
kopano-core 8.5.5-0ubuntu1 all Metapackage to install the Kopano Core stack

Thanks in advance

Best regards