**Version 5.2.21** (December 28th 2016)

* Fix missed number update in version file – no functional changes

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**Version 5.2.20** (December 28th 2016)

* **SECURITY** Critical security update for CVE-2016-10045 please update now! Thanks to [Dawid Golunski](https://legalhackers.com) and Paul Buonopane (Zenexer).

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** Version 5.2.19** (December 26th 2016)

* Minor cleanup

** Version 5.2.18** (December 24th 2016)

* **SECURITY** Critical security update for CVE-2016-10033 please update now! Thanks to [Dawid Golunski](https://legalhackers.com).
* Add ability to extract the SMTP transaction ID from some common SMTP success messages
* Minor documentation tweaks

** Version 5.2.17** (December 9th 2016)

* This is officially the last feature release of 5.2. Security fixes only from now on; use PHPMailer 6.0!
* Allow DKIM private key to be provided as a string
* Provide mechanism to allow overriding of boundary and message ID creation
* Improve Brazilian Portuguese, Spanish, Swedish, Romanian, and German translations
* PHP 7.1 support for Travis-CI
* Fix some language codes
* Add security notices
* Improve DKIM compatibility in older PHP versions
* Improve trapping and capture of SMTP connection errors
* Improve passthrough of error levels for debug output
* PHPDoc cleanup