PIUS 3.0.0 is a major upgrade. This is a full move to python 3 (python 2 is no longer supported). PIUS 3.0.0 also drops all support for GnuPG 1, including support for cached-passphrase and interactive modes (agent mode is now the only mode).
In addition this release supports XDG standards. Specifically the config file is now in XDG_CONFIG_HOME (usually ~/.config/pius/) and the state file is in XDG_DATA_HOME (~/.local/share/pius/) on platforms that support that. We fall back to the previous ~/.pius/ on other platforms.
Options have also been made consistent across binaries and pius-keyring-mgr now supports all the same mail-server options as the other binaries.
All users are encouraged to upgrade.