sh steps stuck indefinitely on uncommon architectures (e.g. s390x)

After upgrading to v1.31, the first sh step in a pipeline gets stuck. After few minutes Console Output shows:

[Pipeline] sh (Get email of the author of last commit)
process apparently never started in /data/jenkins/workspace/TG2_PTG2_-_pipeline_build_master@tmp/durable-be2cf2a6
(running Jenkins temporarily with -Dorg.jenkinsci.plugins.durabletask.BourneShellScript.LAUNCH_DIAGNOSTICS=true might make the problem clearer)
Cannot contact : java.io.FileNotFoundException: File '/data/jenkins/workspace/TG2_PTG2_-_pipeline_build_master@tmp/durable-be2cf2a6/output.txt' does not exist

Eventually, I discovered that a new binary was added in the latest version of this plugin. The script compile-binaries.sh in GitHub suggests that the binary is only built for Linux and MacOS.

Sure enough, when I try to execute the binary myself on an architecture other than amd64, I get:

-bash: /data/jenkins/caches/durable-task/durable_task_monitor_1.31_unix_64: cannot execute binary file

Are other architectures or operating systems (Windows) not supported anymore?