Fixed
- Upgrading from an earlier version in Plugin Manager no longer stops with "Cannot redeclare class". The Upgrade runs the new version's installer in an admin request that already holds the installed version's classes, loaded from that version's folder, so every require of a plugin class now happens only when the class isn't loaded yet. Upgrading from 1.0.0 to this version already works because of it. Nothing else changed: no settings, data or emails.
Upgrade in Plugin Manager: upload the v1.0.1 folder beside v1.0.0, click Upgrade, then Upgrade again on the confirmation screen.