I just found out, that the latest iprint manager only supports TLSv1
AES128-SHA for secure printing and installing the printer. But it
supports TLSv1 RC4-MD5 for administration. Earlier secure printing also
supported TLSv1 RC4-MD5. As TLSv1 AES128-SHA is only available for
Windows XP/ Windows 20003 and later secure printing from these elder
clients fails.

Of course W2K and before is not more supported at all - but from time
to time I have to use some older VMs for reading very old data. Then it
often is quite handy to print those data to paper. So I was quite
astonished, that printing failed without any previous warning, as it
had worked before quite well.

W. Prindl