diff --git a/nixos/modules/services/web-apps/mediawiki.nix b/nixos/modules/services/web-apps/mediawiki.nix
index 54e33a9d56cb..8b494b7c1208 100644
--- a/nixos/modules/services/web-apps/mediawiki.nix
+++ b/nixos/modules/services/web-apps/mediawiki.nix
@@ -493,6 +493,8 @@ in
     services.phpfpm.pools.mediawiki = {
       inherit user group;
       phpEnv.MEDIAWIKI_CONFIG = "${mediawikiConfig}";
+      # https://www.mediawiki.org/wiki/Compatibility
+      phpPackage = pkgs.php81;
       settings = (if (cfg.webserver == "apache") then {
         "listen.owner" = config.services.httpd.user;
         "listen.group" = config.services.httpd.group;