Hi Klaus,

Cups (since 1.3.4) does not support iso8859 encodings anymore. So any client needs to be able to send UTF-8-encoded content.

You wrote that SAP on the same SLES12 server is one of the sources of non-UTF-8 user names - I suggest to contact them, it may well be that they're passing through umlaut-containing user names from MS Windows environments in a binary fashion. This would need fixing in the SAP layer, either by converting when receiving such "content" by a UTF-8 component (SAP on a UTF-8 server) or when handing out to other subsystems on such a server (i.e. when forwarding data to CUPS).

I don't have any details, but probably they have this covered for the actual printing data and just omitted conversions for user names...