diff --git a/src/Issue/IssueService.php b/src/Issue/IssueService.php
index 28e1a46..0aec539 100644
--- a/src/Issue/IssueService.php
+++ b/src/Issue/IssueService.php
@@ -1154,12 +1154,16 @@ public function getIssueSecuritySchemes($securityId)
     public function updateLabels($issueIdOrKey, $addLablesParam, $removeLabelsParam, $notifyUsers = true)
     {
         $labels = [];
-        foreach ($addLablesParam as $a) {
-            array_push($labels, ['add' => $a]);
+        if ($addLablesParam !== null) {
+            foreach ($addLablesParam as $a) {
+                array_push($labels, ['add' => $a]);
+            }
         }
 
-        foreach ($removeLabelsParam as $r) {
-            array_push($labels, ['remove' => $r]);
+        if ($removeLabelsParam !== null) {
+            foreach ($removeLabelsParam as $r) {
+                array_push($labels, ['remove' => $r]);
+            }
         }
 
         $postData = json_encode([
@@ -1192,12 +1196,16 @@ public function updateLabels($issueIdOrKey, $addLablesParam, $removeLabelsParam,
     public function updateFixVersions($issueIdOrKey, $addFixVersionsParam, $removeFixVersionsParam, $notifyUsers = true)
     {
         $fixVersions = [];
-        foreach ($addFixVersionsParam as $a) {
-            array_push($fixVersions, ['add' => ['name' => $a]]);
+        if ($addFixVersionsParam !== null) {
+            foreach ($addFixVersionsParam as $a) {
+                array_push($fixVersions, ['add' => ['name' => $a]]);
+            }
         }
 
-        foreach ($removeFixVersionsParam as $r) {
-            array_push($fixVersions, ['remove' => ['name' => $r]]);
+        if ($removeFixVersionsParam !== null) {
+            foreach ($removeFixVersionsParam as $r) {
+                array_push($fixVersions, ['remove' => ['name' => $r]]);
+            }
         }
 
         $postData = json_encode([