Based on https://github.com/zendframework/zend-form/releases/tag/release-2.3.9 (commit 70220ffb8f25cb295184f95b4ce277b807f32dd9 in this repo)

- [zendframework/zend-form#7506](https://github.com/zendframework/zf2/pull/7506) resolves issues when UTF-8 values are used in Mail headers, particularly addresses.
- [zendframework/zend-form#7507](https://github.com/zendframework/zf2/pull/7507) ensures that array values can be used with cookies.
- [zendframework/zend-form#7514](https://github.com/zendframework/zf2/pull/7514) ensures that multipart MIME messages can be added to `Laminas\Mail\Message` instances in such a way that they do not conflict with ZF2015-04.