Fix redirects.

README.md

 * [Fetch](https://github.com/tedious/Fetch) - An IMAP library.
 * [Mautic](https://github.com/mautic/mautic) - Email marketing automation
 * [PHPMailer](https://github.com/PHPMailer/PHPMailer) - Another mailer solution.
-* [Stampie](https://github.com/Stampie/Stampie) - A library for email services such as [SendGrid](https://sendgrid.com/), [PostMark](https://postmarkapp.com), [MailGun](https://www.mailgun.com/) and [Mandrill](https://www.mandrill.com).
+* [Stampie](https://github.com/Stampie/Stampie) - A library for email services such as [SendGrid](https://sendgrid.com/), [PostMark](https://postmarkapp.com), [MailGun](https://www.mailgun.com/) and [Mandrill](https://mailchimp.com/features/transactional-email/).
 * [SwiftMailer](https://swiftmailer.symfony.com) - A mailer solution.
 
 ### Files
 * [Alice](https://github.com/nelmio/alice) - An expressive fixture generation library.
 * [AspectMock](https://github.com/Codeception/AspectMock) - A mocking framework for PHPUnit/Codeception.
 * [Atoum](https://github.com/atoum/atoum) - A simple testing library.
-* [Behat](http://docs.behat.org/en/v2.5/) - A behaviour driven development (BDD) testing framework.
+* [Behat](https://docs.behat.org/en/latest/) - A behaviour driven development (BDD) testing framework.
 * [Codeception](https://github.com/Codeception/Codeception) - A full stack testing framework.
 * [Faker](https://github.com/fzaninotto/Faker) - A fake data generator library.
 * [HTTP Mock](https://github.com/InterNations/http-mock) - A library for mocking HTTP requests in unit tests.
 
 * [CircleCI](https://circleci.com) - A continuous integration platform.
 * [GitlabCi](https://about.gitlab.com/stages-devops-lifecycle/continuous-integration/) - Let GitLab CI test, build, deploy your code. TravisCi like.
-* [Jenkins](https://jenkins.io/index.html) - A continuous integration platform with [PHP support](http://jenkins-php.org/index.html).
+* [Jenkins](https://www.jenkins.io/) - A continuous integration platform with [PHP support](https://www.jenkins.io/solutions/php/).
 * [JoliCi](https://github.com/jolicode/JoliCi) - A continuous integration client written in PHP and powered by Docker.
 * [PHPCI](https://github.com/dancryer/phpci) - An open source continuous integration platform for PHP.
 * [SemaphoreCI](https://semaphoreci.com/) - A continuous integration platform for open source and private projects.