PHP issues by PHP Compatibility Checker

PHP Compatibility Checker gave the following issues for PHP 7,

FILE: /../wp-content/plugins/w3-total-cache/inc/email/minify_error_notification.php
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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1 | WARNING | No PHP code was found in this file and short open tags are not allowed by this install of PHP. This file may be using short open tags but PHP does not allow them.
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FILE: /../wp-content/plugins/w3-total-cache/inc/options/common/footer.php
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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1 | WARNING | No PHP code was found in this file and short open tags are not allowed by this install of PHP. This file may be using short open tags but PHP does not allow them.
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FILE: /../wp-content/plugins/w3-total-cache/inc/popup/common/footer.php
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FOUND 0 ERRORS AND 1 WARNING AFFECTING 1 LINE
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1 | WARNING | No PHP code was found in this file and short open tags are not allowed by this install of PHP. This file may be using short open tags but PHP does not allow them.
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FILE: /../wp-content/plugins/w3-total-cache/lib/Azure/MicrosoftAzureStorage/Common/Internal/Utilities.php
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FOUND 0 ERRORS AND 2 WARNINGS AFFECTING 1 LINE
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710 | WARNING | Function mcrypt_encrypt() is deprecated since PHP 7.1; use OpenSSL instead
710 | WARNING | Extension ‘mcrypt’ is deprecated since PHP 7.1 – use openssl (preferred) or pecl/mcrypt once available instead.
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