diff --git a/composer.json b/composer.json
index 7876b6e..b30882f 100644
--- a/composer.json
+++ b/composer.json
@@ -25,7 +25,7 @@
         "silverstripe/framework": "^4.10",
         "monolog/monolog": "~1.15",
         "ptcinc/solr-php-client": "^1.0",
-        "symfony/process": "^3.2",
+        "symfony/process": "^3.2 || ^4",
         "tractorcow/silverstripe-proxy-db": "~0.1"
     },
     "require-dev": {
diff --git a/src/Solr/Reindex/Handlers/SolrReindexImmediateHandler.php b/src/Solr/Reindex/Handlers/SolrReindexImmediateHandler.php
index 8bd2520..ca610cd 100644
--- a/src/Solr/Reindex/Handlers/SolrReindexImmediateHandler.php
+++ b/src/Solr/Reindex/Handlers/SolrReindexImmediateHandler.php
@@ -95,9 +95,16 @@ class SolrReindexImmediateHandler extends SolrReindexBase
         $scriptPath = sprintf("%s%scli-script.php", $frameworkPath, DIRECTORY_SEPARATOR);
         $scriptTask = "{$php} {$scriptPath} dev/tasks/{$taskName}";
 
-        $cmd = "{$scriptTask} index={$indexClassEscaped} class={$class} group={$group} groups={$groups} variantstate={$statevar}";
-        $cmd .= " verbose=1";
-        $logger->info("Running '$cmd'");
+        $cmd = [
+            $scriptTask,
+            "index={$indexClassEscaped}",
+            "class={$class}",
+            "group={$group}",
+            "groups={$groups}",
+            "variantstate={$statevar}",
+            "verbose=1"
+        ];
+        $logger->info('Running ' . implode(' ', $cmd));
 
         // Execute script via shell
         $process = new Process($cmd);