diff --git a/src/Admin_Tools_Command.php b/src/Admin_Tools_Command.php
index a8eec72..0754125 100644
--- a/src/Admin_Tools_Command.php
+++ b/src/Admin_Tools_Command.php
@@ -85,6 +85,13 @@ private function install() {
 		if ( ! is_file( $index_file ) || file_get_contents( $index_file ) !== $index ) {
 			$this->fs->dumpFile( $index_file, $index );
 		}
+
+		// A phpRedisAdmin config written by an older release lacks allow_no_auth, which pra 1.27.0+ needs to serve.
+		$pra_config_file = ADMIN_TOOL_DIR . '/pra/includes/config.inc.php';
+		$pra_config      = file_get_contents( ADMIN_TEMPLATE_ROOT . '/pra.config.mustache' );
+		if ( is_file( $pra_config_file ) && file_get_contents( $pra_config_file ) !== $pra_config ) {
+			$this->fs->dumpFile( $pra_config_file, $pra_config );
+		}
 	}
 
 	/**
diff --git a/templates/pra.config.mustache b/templates/pra.config.mustache
index eafcec6..610952c 100644
--- a/templates/pra.config.mustache
+++ b/templates/pra.config.mustache
@@ -11,6 +11,9 @@ if (!empty($admin_user)) {
 'password' => $admin_pass,
 ),
 );
+} else {
+  // phpRedisAdmin 1.27.0+ refuses to run without a login; /ee-admin/ is already behind EasyEngine's admin-tools basic auth.
+  $config['allow_no_auth'] = true;
 }
 
 $config['servers'] = array();