KOPANO does not start after upgrading from UCS 4.4.9 to 5.0.2

After updating kopano does not start anymore. I get this message:
“K-2170: soap_ssl_server_context: SSL/TLS error (Can’t find or read certificate in private key PEM file). OpenSSL says: (null).”

in /etc/kopano/ssl are 3 files:
-rw-r----- 1 kopano kopano 5340 Nov 26 2019 cert.pem
-rw------- 1 kopano kopano 1679 Nov 26 2019 private.key
-rw------- 1 kopano kopano 7019 Nov 26 2019 server.pem

both pem-Files are SHA1-encrypted. Could this be the problem? How to solve this?

I’m not sure if it is the best way to do it, but here is how I solved the problem.

  1. Backup kopano ssl config
cp -a /etc/kopano/ssl /etc/kopano/"ssl_$(date +%Y%m%d)"
  1. Copy univention SSLs of master to kopano directory
cp /etc/univention/ssl/[YOUR_FQHN]/* /etc/kopano/ssl/
  1. create server.pem
cd /etc/kopano/ssl/
cat private.key > server.pem
cat cert.pem >> server.pem
  1. change owner
cd /etc/kopano/ssl/
chown kopano:kopano *
  1. Restart kopano-server and check status
systemctl restart kopano-server
systemctl status kopano-server

First (before the update), I had to re-create all SSL certificates:

eval "$(ucr shell domainname ssl/default/days)"
cd  /etc/univention/ssl
for i in *".${domainname}"; do   univention-certificate new -name "$i" -days "${ssl_default_days}"; done

And then follow all other steps of Renewing the SSL certificates (but use univention-certificate new instead of univention-certificate new as shown above)