This Comet Cache release candidate includes 5 new features, 4 bug fixes, 10 enhancements, and improved compatibility with WP-CLI, Comment Mail, and PHP. Most notable in this release is a completely new option panel: Apache Optimizations. You can download and try out this release using the link below. Please report bugs and feedback on GitHub.

Comet Cache Pro testers: Don't forget that you can automatically receive Release Candidates by telling the Comet Cache Plugin Updater to check for Release Candidates in Comet Cache → Plugin Updater → Beta Testers.


Lite: Comet Cache Lite v160629-RC

Pro: Comet Cache Pro v160629-RC (you must be logged into your account at to access this download)

Installation Instructions

  1. Deactivate and Delete any existing Comet Cache plugin via Dashboard → Plugins
  2. Download the release candidate using the link above
  3. Install the release candidate you downloaded by going to Dashboard → Plugins → Add New → Upload and selecting the downloaded zip file
  4. Activate Comet Cache

Changelog for Comet Cache v160629-RC (Release Candidate)

  • New Feature! Apache Optimizations. This release includes a completely new option panel for Apache Performance Tuning. Current options for Apache tuning include GZIP Compression, Leverage Browser Caching, Enforce Canonical URLs, and Send Access-Control-Allow-Origin Header (for Static CDN Filters). These options automatically add or remove from your .htaccess file the appropriate configuration based on the options you enable or disable (all options are disabled by default, so your .htaccess file is not modified unless you say so). If you prefer to update your .htaccess file manually, the necessary configuration can be viewed beneath each option. Props @jaswsinc, @renzms. See Issue #789.
  • New Feature! A new "Enable GZIP Compression" option has been added to the new Apache Optimizations panel. This option will automatically add the appropriate configuration to your .htaccess file to enable GZIP compression. This option is disabled by default. The old "GZIP Compression" panel has been removed in favor of the new option inside Apache Optimizations. Props @renzms, @jaswsinc. See Issue #764.
  • New Feature! Multisite Host Exclusion Patterns. It's now possible to exclude entire sites from the cache in a Multisite Network environment. Domain mapping is also supported! See Comet Cache → Plugin Options → Host Exclusion Patterns. If you're running a Multisite Network with Sub-Directories, you can exclude sites using the existing URI Exclusion Patterns feature. Props @kristineds. See Issue #754.
  • New Feature (Pro)! A new "Leverage Browser Caching" option has been added to the new Apache Optimizations panel. This option will automatically add the appropriate configuration to your .htaccess file to enable Browser Caching. This option is disabled by default. Props @renzms, @jaswsinc. See Issue #764.
  • New Feature (Pro)! A new "Enforce Canonical URLs" option has been added to the new Apache Optimizations panel. This options adds the appropriate .htaccess code to enforce the correct canonical URLs according to your WordPress Permalink settings (Comet Cache detects if the Permalink Structure ends with a trailing slash, or without a trailing slash). Props @renzms, @jaswsinc. See Issue #554.
  • Bug Fix: In some scenarios the Cron Event that cleans up expired cache files (_cron_comet_cache_cleanup) would never run, or the Next Run time would constantly reset to 1 minute away from running every time a page was reloaded. We suspect this is a race condition and in attempt to work around this issue we now skip all of our Cron-related checks if Cron is currently in the middle of running a process. Props @xberg and @lkraav for help reporting. See Issue #653.
  • Bug Fix: If your site uses aliased domains, Comet Cache now properly considers all possible domain variations when it clears the cache on WP Standard installations. Props @kristineds, @jaswsinc, @yoffe, and @VR51. See Issue #608.
  • Bug Fix (Pro): Fixed a bug where Comet Cache would appear to prevent WordPress from redirecting Permalinks that don't include a trailing slash, to the URL that does include a trailing slash. This was due to the fact that Comet Cache loads very early on (for caching purposes) and as a result the WordPress redirect_canonical() function never gets run. This was fixed by adding an option to the new Apache Optimizations panel that allows you to Enforce Canonical URLs. Props @renzms, @jaswsinc. See Issue #554.
  • UX Bug Fix (Pro): If you had your WordPress Dashboard login details saved by your browser, the browser autofill would automatically fill in the Pro Plugin Updater fields with those details, which then needed to be replaced with your actual Pro license details. The browser autofill has been disabled for those fields (tested in Chrome, Firefox, and Safari). Props @renzms. See Issue #741.
  • Enhancement: Added links the Options Page for the Comet Cache Twitter and Facebook accounts. Props @renzms. Issue #771.
  • Enhancement: Added full support for UTF-8 (multibyte strings). This release adds full support for UTF-8 throughout the Comet Cache codebase, greatly enhancing Comet Cache's ability to deal with file paths and URLs that may contain UTF-8 characters. Props @jaswsinc. Issue #703.
  • UI Enhancements: Improved the Logged-In Users and the Client-Side Caching options panels to dim additional options when the feature is disabled. Additionally, the "Enable HTML Compression for Logged-In Users?" option has been relocated from the HTML Compressor option panel to the more appropriate Logged-In Users option panel. See Issue #768.
  • UX Enhancement: Improved the inline docs for Auto-Clear List of Custom URLs to clarify that full URLs must be provided. Props @renzms. See Issue #781.
  • Enhancement (Pro): The Pro Plugin Updater has been improved to allow for better compatibility with hosting platforms that use Apache's ModSecurity. In some cases, site owners were seeing a 404 error when attempting to update the Pro version using the Pro Plugin updater because certain ModSecurity rules were blocking the Pro Updater requests. The Pro Plugin Updater now uses WP Transients to store the necessary metadata, which works around the issue with ModSecurity. Props to @seozones for reporting and @jaswsinc for help fixing this. Issue #416.
  • Enhancement (Pro): When Static CDN Filters are enabled, it's now possible to disable the automatic insertion of rules into your .htaccess file that are designed to prevent issues with CORS. See Apache Optimizations → Send Access-Control-Allow-Origin Header? See Issue #789.
  • Enhancement (Pro): The HTML Notes added to the bottom of a cached page now specify if the page was cached as the result of an HTTP Request or if it was cached by the Auto-Cache Engine. Props @kristineds. See Issue #292.
  • Enhancement (Pro): The Auto-Cache Engine now supports a fallback to cURL using the WP HTTP API. If your PHP configuration has allow_fopen_url=0, the Auto-Cache Engine will use the fallback to download the XML Sitemap and parse it from a temporary file. If you want to force the use of this fallback even when allow_fopen_url=1, you can use a filter. See Issue #440.
  • UI Enhancement (Pro): A second button has been added to the bottom of the Pro Plugin Updater page that allows you to "Save and Update Comet Cache Pro" in one step. Props @renzms. See Issue #741.
  • UI Enhancement (Pro): The "Cache Stats" button in Admin Bar is now linked to the Cache Stats page. Instead of hovering over the button and then clicking "More Info" inside the popup panel, you can now just click the "Cache Stats" button to go directly to the Cache Stats page. Props @Presskopp, @renzms. See Issue #780.
  • Comment Mail Compatibility: Improved compatibility with the Comment Mail plugin by automatically clearing the cache whenever Comment Mail options are changed. Many of the Comment Mail options affect front-end portions of the site, so it's important that the cache is cleared whenever Comment Mail options change. See Comment Mail Issue #278.
  • PHP Compatibility: Improved compatibility back to PHP 5.2 (the lowest version allowed by WordPress). Comet Cache still requires PHP 5.4+, but if you install Comet Cache on a site running PHP 5.2, it will now fail gracefully with a Dashboard notice indicating PHP 5.4+ is required, instead of producing a fatal error. See Issue #784.
  • WP-CLI Compatibility: Fixed a bug with deactivating Comet Cache using WP-CLI. Doing so was producing a "Invalid argument; host token empty!" error message. This has been resolved. Props @MarioKnight @jaswsinc @renzms. See Issue #728.
  • Renamed COMET_CACHE_ALLOW_BROWSER_CACHE constant to COMET_CACHE_ALLOW_CLIENT_SIDE_CACHE. Backwards compatibility has been maintained.
  • Renamed allow_browser_cache plugin option to allow_client_side_cache.

Please note that when this version leaves beta and an official release is made, the WordPress Plugin Updater will automatically detect the new version on and ask you to upgrade (applies to Comet Cache Lite). If you're using Comet Cache Pro, please configure the Pro Plugin Updater (Dashboard → Comet Cache → Plugin Updater) so that you are notified when there is a new official release.

Please report bugs and feedback on GitHub.