Please note, the dependencies are not satisfied with libcurl version 3 if libcurl4 is used with other programs (php7.3-curl, clamav, percona-server, ... for example).

Libcurl 3 and 4 can not be installed at the same time.

A release with libcurl4 as dependency would be really great, I have to maintain a VM in stretch for my instance at the moment after dist-upgrading from stretch to buster :-)

Do you have any ETA to provide ?

Anyway, thank you for the work and your kind replies, guyz.

I found that sogo provided by debian depends on "libcurl3-gnutls" which can be installed with libcurl4 at the same time.

Maybe nightly edition can build with that?

Try:

http://packages.inverse.ca/SOGo/nightly/4/debian/pool/buster/

Works for me !

Thanks !