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Do not advertise unmaintained extensions
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Do not advertise PEAR as an installation method
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Cleanup upgrading section(s)
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Update installation instructions for vfsStream to use Composer
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Rephrase
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Leftover from 05bffa8
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assertNotFalse() and assertNotTrue() were introduced in PHPUnit 4.0
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More work on documentation for strict mode and risky tests
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switches -> options
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