This PR was squashed before being merged into the 2.3.x-dev branch (closes #1607).

Discussion
----------

Drop support for older versions of PHP and Symfony

Let's make it much simpler to maintain future versions of Silex. This pull request does the following (@Ocramius would be proud of me :)):

 * drop support for Twig < 2.0
 * drop support for PHP < 7.1
 * drop support for Symfony 2.x and 3.x

Commits
-------

816f4591 removed obsolete code
63851cc6 use namespaced PHPUnit
182ecf05 removed obsolete code
f1f9ce42 dropped support for older versions of PHP and Symfony

This PR was squashed before being merged into the 2.3.x-dev branch (closes #1614).

Discussion
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Use ServiceIterator in Security provider for voters

Fixes #1530.

Commits
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e2c48152 Use ServiceIterator in Security provider for voters

This PR was merged into the 2.3.x-dev branch.

Discussion
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Check for HttpKernelRuntime before using it in Twig runtimes

Fixes #1448.

This fixes an incompatibility with Symfony Twig bridge prior to 3.2.

The HttpKernelRuntime was introduced in https://github.com/silexphp/Silex/commit/72d7746ec216da230221c19aa6e3092b55596070.
It included checks whether the class exists, but not in the Twig runtimes list.

Commits
-------

18ab3f6e Check for HttpKernelRuntime before using it in Twig runtimes

This PR was merged into the 2.3.x-dev branch.

Discussion
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Sync provider parameters in docs

This documents all parameter options to providers which were missing from the documentation.

Commits
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ff52920e Sync provider parameters in docs

This PR was merged into the 2.3.x-dev branch.

Discussion
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Allow setting custom status code on exception response

Closes #1450.

Prior and related PRs and issues:

- https://github.com/symfony/symfony/pull/19822
- https://github.com/symfony/symfony-docs/commit/5f0becf3233238a9d96cba39f3146a0e7ae03763
- https://github.com/symfony/symfony-docs/pull/9336

Commits
-------

71035117 Allow setting custom status code on exception response

This documents all parameter options to providers
which were missing from the documentation.

Prior and related PRs and issues:

- https://github.com/symfony/symfony/pull/19822
- https://github.com/symfony/symfony-docs/commit/5f0becf3233238a9d96cba39f3146a0e7ae03763
- https://github.com/symfony/symfony-docs/pull/9336
- https://github.com/silexphp/Silex/issues/1450

This fixes an incompatibility with Symfony Twig bridge prior to 3.2.

The HttpKernelRuntime was introduced in https://github.com/silexphp/Silex/commit/72d7746ec216da230221c19aa6e3092b55596070.
It included checks whether the class exists, but not in the Twig runtimes list.

This PR was squashed before being merged into the 2.3.x-dev branch (closes #1608).

Discussion
----------

Make CSRF extension work with Validator translations domain

- Make Validator translation domain configurable
- Fix #1569.

Commits
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935caf7b Make CSRF extension work with Validator translations domain

This PR was merged into the 2.3.x-dev branch.

Discussion
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Fix Security provider context usage

Fixes #1568.

The `'context'` parameter is defaulting to the `'name'` parameter, but then it wasn't used properly below.

Commits
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d92d5c5a Fix Security provider context usage

This PR was merged into the 2.3.x-dev branch.

Discussion
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Link to current documention of Symfony components

Prefer the latest Symfony documentation instead of a specific version which can easily become outdated.

Commits
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b2dc9445 Link to current documention of Symfony components

Fixes https://github.com/silexphp/Silex/issues/1568

This PR was merged into the 2.3.x-dev branch.

Discussion
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Add support for Symfony 4.0

Commits
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7c6a06a9 added support for Symfony 4.0

This reverts commit d72829f9, reversing
changes made to 570cffad.

This PR was squashed before being merged into the 2.2.x-dev branch (closes #1362).

Discussion
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Added monolog.formatter.output and monolog.formatter.dateformat param…

…eters to format the line

Commits
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b4f5a709 Added monolog.formatter.output and monolog.formatter.dateformat param…

This PR was merged into the 2.2.x-dev branch.

Discussion
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Fix validator integration into the security provider

replaces #1550, fixes #1531

Commits
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8166816e fixed validator integration into the security provider

This PR was merged into the 2.2.x-dev branch.

Discussion
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Fix Twig provider on Symfony 3.4

replaces #1571, closes #1579

Commits
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7e12bbd5 fixed Twig provider on Symfony 3.4

This PR was merged into the 2.2.x-dev branch.

Discussion
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Fix deprecations on the translation provider

Commits
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f0f2a2cf fixes deprecations on the translation provider

This PR was merged into the 2.2.x-dev branch.

Discussion
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Fix PHPUnit warning

Commits
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db01e507 fixed PHPUnit warning

This PR was merged into the 2.2.x-dev branch.

Discussion
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Fix deprecations in SecurityServiceProvider tests

Commits
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e44cce3b fixed deprecations in SecurityServiceProvider tests