[Samba] classicupgrade fails in sernet-samba 4.11 on CentOS 8, Python 3 bug?

[Ralf Spenneberg (Samba)]

Hi,

we might have encountered a possible python 3 bug in samba 4.11. We are
using the sernet-samba packages.
While the classicupgrade works on centos6 (using python 2) it fails on
centos8 (using python3) with a classic python3 bug message:

# samba-tool domain classicupgrade --dbdir=pdc-files/ --realm=ad.xxx.de
--dns-backend=SAMBA_INTERNAL pdc-files/smb.conf
INFO 2019-09-25 06:15:34,366 pid:12017
/usr/lib64/python3.6/site-packages/samba/netcmd/domain.py #1684: Reading
smb.conf
Unknown parameter encountered: "display charset"
Ignoring unknown parameter "display charset"
Unknown parameter encountered: "idmap alloc backend"
Ignoring unknown parameter "idmap alloc backend"
INFO 2019-09-25 06:15:34,368 pid:12017
/usr/lib64/python3.6/site-packages/samba/netcmd/domain.py #1688:
Provisioning
ERROR(<class 'TypeError'>): uncaught exception - a bytes-like object is
required, not 'str'
  File "/usr/lib64/python3.6/site-packages/samba/netcmd/__init__.py",
line 185, in _run
    return self.run(*args, **kwargs)
  File "/usr/lib64/python3.6/site-packages/samba/netcmd/domain.py", line
1690, in run
    useeadb=eadb, dns_backend=dns_backend, use_ntvfs=use_ntvfs)
  File "/usr/lib64/python3.6/site-packages/samba/upgrade.py", line 477,
in upgrade_from_samba3
    ldappass = ldappass.strip('\x00')

Any hints what could be done to achieve the classicupgrade?

Kind regards,

Ralf