Is anyone still making use of UNIX System V R4 binaries on FreeBSD? The System V Release from the late 80's... The FreeBSD developers have been trying to find out if anyone is still serious about using SVR4 binary compatibility on FreeBSD, but so far they haven't been able to find parties that are still truly caring.
With an initiative led by FreeBSD developer Gleb Smirnoff, they are hoping to remove the SVR4 binary compatibility layer from FreeBSD head, meaning it will impact FreeBSD 12.0 as the first affected release. He expressed the interest in doing so on the mailing list.
FreeBSD developers have kept this SVR4 binary compatibility support so it can keep building under FreeBSD, but there isn't anyone known that's actually verifying the functionality and there are no regression tests with apparently no users. Smirnoff had discovered recently that at least the socket layer compatibility has been broken for a number of years too, further indicating that no one is probably making use of the code.
With no solid testing and vetting of the code, it's also believed there are potential security issues, further motivating FreeBSD developers to strip out the SVR4 binary support.