Processing.org no longer supports Arm version see below, taken from download page:-
Earlier releases have been removed because we can only support the current versions of the software. To update old code, read the [ changes ](https://github.com/processing/processing/wiki/Changes) page. Changes for each release can be found in [revisions.txt](https://raw.githubusercontent.com/processing/processing/master/build/shared/revisions.txt). If you have problems with the current release, please [file a bug](https://github.com/processing/processing/issues?q=is%3Aopen) so that we can fix it. Older releases can also be [built from the source](https://github.com/processing/processing).
See also P4 on Pi4 (is not a joke)