Really AM? Can you atleast Google the term before you declare it a typo to see if it makes sense in the sentence? :-)

Also see MAINTENANCE BRANCHES.

Patches that break binary compatibility are not acceptable. (Please talk to a pumpking.)

Perl's [C] API is same whether you are running Perl on z/OS or Perl on NetWare. Perl's ABI absolutely isn't compatible between Perl on z/OS and Perl on NetWare.