The ELF format isn't the one that I'm the most concerned about, but for example compressed sections were updated in the past decade. The ABI for x86-64 is out-of-date (actually, the site it links to is now a 404, but my recollection was that was a version around 2013)--missing things like _Float16 rules, DWARF register naming for AMX and APX registers, microarchitecture levels, new relocation types,