Pony 0.21.2 is a recommended update. It fixes an issue introduced in 0.21.1 that could result in programs not shutting down as expected.

Don't suspend schedulers if terminating and reset steal_attempts on wake

Pony 0.21.1 introduced dynamic scheduler thread scaling. As part of that change, a bug was introduced that could result in a program not shutting down.

[0.21.2] - 2017-12-25

Fixed

• Don't suspend schedulers if terminating and reset steal_attempts on wake (PR #2447)