Peter has sent me the file with the old version labels that had been created by Andrea before.
Now everything works and apt-get (or Synaptic) is willing to work with my packages again ...
I am very glad this has turned out working and I hope someone will soon incorporate the workaround in the official version of hplip.
Thanks so much to @hotzplotz and @pdqharvey!
Peter has sent me the file with the old version labels that had been created by Andrea before.
Now everything works and apt-get (or Synaptic) is willing to work with my packages again ...
I am very glad this has turned out working and I hope someone will soon incorporate the workaround in the official version of hplip.
thx for all your efforts!
piedro