Hello,

I have zillions of notebooks collected over many years that I occasionally like to use, written for old versions of Mathematica, like 6 or 7. Newer versions are not necessarily compatible (and sometimes are considerably slower), and since I don't like to recode hundreds of megabytes of programs, I used to connect the newer frontends to those old kernels. This worked all fine until Mathematica 12 came out, for which it turned out that the frontend does not connect any more to the old kernels (64 bit of course). I am not sure whether the connection protocol has changed, or whether some macOS security feature steps in.

Is there a workaround? The dilemma is that from macOS 10.15 onwards, the 32 bit frontends won't work any more, which means that a large amount of proven old code will become unusuable.

Thanks! W.