Title: PHP 8.0 Update doesn’t work Last modified: April 19, 2022 --- # PHP 8.0 Update doesn’t work * Resolved [dopblog](https://wordpress.org/support/users/dopblog/) * (@dopblog) * [4 years, 1 month ago](https://wordpress.org/support/topic/php-8-0-update-doesnt-work/) * Dear Polylang crew, * I’m running Polylang on this site and need to update it to PHP 8.0. But after I do that the site stops working… See error message below. When deactivating Polylang the problem does not occur. * I’m using the Theme Laytheme and all plugins are up-to-date. Any ideas on what I could do now? * Thank you so much! — Ben * ____ * ``` Fatal error: Uncaught ValueError: version_compare(): Argument #3 ($operator) must be a valid comparison operator in /homepages/36/d812209104/htdocs/PRACTICE844579/wp- content/plugins/polylang-slug/polylang-slug.php:31Stacktrace:#0 /homepages/36/d812209104/htdocs/PRACTICE844579/wp-content/plugins/polylang- slug/polylang-slug.php(31):version_compare('3.2.1','1.7','=<')#1 /homepages/36/d812209104/htdocs/PRACTICE844579/wp-settings.php(418): include_once('/homepages/36/d...')#2 /homepages/36/d812209104/htdocs/PRACTICE844579/wp-config.php(86): require_once('/homepages/36/d.…')#3 /homepages/36/d812209104/htdocs/PRACTICE844579/wp-load.php(50): require_once(/homepages/36/d.')#4 /homepages/36/d812209104/htdocs/PRACTICE844579/wp-blog-header.php(13): require_once('/homepages/36/d..')#5 /homepages/36/d812209104/htdocs/PRACTICE844579/index.php(17): require('/homepages/36/d…..')#6{main}thrownin /homepages/36/d812209104/htdocs/PRACTICE844579/wp-content/plugins/polylang- slug/polylang-slug.php on line 31 There has been a critical error on this website. ``` - This topic was modified 4 years, 1 month ago by [dopblog](https://wordpress.org/support/users/dopblog/). * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fphp-8-0-update-doesnt-work%2F%3Foutput_format%3Dmd&locale=en_US) to see the link]_ Viewing 9 replies - 1 through 9 (of 9 total) * [Ulrich](https://wordpress.org/support/users/grapplerulrich/) * (@grapplerulrich) * [4 years, 1 month ago](https://wordpress.org/support/topic/php-8-0-update-doesnt-work/#post-15571433) * Hi Ben * You need to update the plugin [Polylang-Slug](https://github.com/grappler/polylang-slug/). Version 0.2.3 is compatible with PHP 8. - This reply was modified 4 years, 1 month ago by [Ulrich](https://wordpress.org/support/users/grapplerulrich/). - This reply was modified 4 years, 1 month ago by [Ulrich](https://wordpress.org/support/users/grapplerulrich/). * Thread Starter [dopblog](https://wordpress.org/support/users/dopblog/) * (@dopblog) * [4 years, 1 month ago](https://wordpress.org/support/topic/php-8-0-update-doesnt-work/#post-15571528) * Fantastic! That was it. Thank you so much Ulrich for the quick hilp. * Thread Starter [dopblog](https://wordpress.org/support/users/dopblog/) * (@dopblog) * [4 years, 1 month ago](https://wordpress.org/support/topic/php-8-0-update-doesnt-work/#post-15575642) * Oh no, I cheered too soon. * After I installed Polylang-Slug 0.2.3 the PHP 8.0 update didn’t crash the site and I thought problem solved. * But the site isn’t multilanguage anymore! Instead of the language switcher there’s just ‘Languages’. * Any idea what broke in the process? * Best — Ben * [Ulrich](https://wordpress.org/support/users/grapplerulrich/) * (@grapplerulrich) * [4 years, 1 month ago](https://wordpress.org/support/topic/php-8-0-update-doesnt-work/#post-15575715) * I am not sure what you mean with “Instead of the language switcher there’s just‘ Languages’.” * The language switcher on the front end seems to working, but you have reverted your changes. * Thread Starter [dopblog](https://wordpress.org/support/users/dopblog/) * (@dopblog) * [4 years, 1 month ago](https://wordpress.org/support/topic/php-8-0-update-doesnt-work/#post-15575728) * Wow what a weird error. * When I’m logged in to WordPress everything’s fine. If not, the language switcher is gone. * What could that be? * [Ulrich](https://wordpress.org/support/users/grapplerulrich/) * (@grapplerulrich) * [4 years, 1 month ago](https://wordpress.org/support/topic/php-8-0-update-doesnt-work/#post-15575764) * The problem seems to be only on the front page. The language switcher on the subpages looks fine. * Thread Starter [dopblog](https://wordpress.org/support/users/dopblog/) * (@dopblog) * [4 years, 1 month ago](https://wordpress.org/support/topic/php-8-0-update-doesnt-work/#post-15575801) * Right, the problem occurs only on three pages Home/Teachers/Prices * I will try to find what’s different on those pages. No idea so far. * Thread Starter [dopblog](https://wordpress.org/support/users/dopblog/) * (@dopblog) * [4 years, 1 month ago](https://wordpress.org/support/topic/php-8-0-update-doesnt-work/#post-15575806) * Or can you maybe point me in a direction? The fact that the problem disappears when I log in seems quite special to me. What changes when an admin is logged in? * [Ulrich](https://wordpress.org/support/users/grapplerulrich/) * (@grapplerulrich) * [4 years, 1 month ago](https://wordpress.org/support/topic/php-8-0-update-doesnt-work/#post-15575849) * And it is only on the English pages. The German page seem to work fine. * Unfortunately, I can’t think of anything that might be causing it. Do you get any errors on those pages? Here is the documentation on how to enable debugging: [https://wordpress.org/support/article/debugging-in-wordpress/](https://wordpress.org/support/article/debugging-in-wordpress/) Viewing 9 replies - 1 through 9 (of 9 total) The topic ‘PHP 8.0 Update doesn’t work’ is closed to new replies. * ![](https://ps.w.org/polylang/assets/icon-256x256.png?rev=3433336) * [Polylang](https://wordpress.org/plugins/polylang/) * [Frequently Asked Questions](https://wordpress.org/plugins/polylang/#faq) * [Support Threads](https://wordpress.org/support/plugin/polylang/) * [Active Topics](https://wordpress.org/support/plugin/polylang/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/polylang/unresolved/) * [Reviews](https://wordpress.org/support/plugin/polylang/reviews/) ## Tags * [php](https://wordpress.org/support/topic-tag/php/) * [update](https://wordpress.org/support/topic-tag/update/) * 9 replies * 2 participants * Last reply from: [Ulrich](https://wordpress.org/support/users/grapplerulrich/) * Last activity: [4 years, 1 month ago](https://wordpress.org/support/topic/php-8-0-update-doesnt-work/#post-15575849) * Status: resolved