diff --git a/application/src/Api/Adapter/AbstractEntityAdapter.php b/application/src/Api/Adapter/AbstractEntityAdapter.php
index 7fcc24793..9bca79153 100644
--- a/application/src/Api/Adapter/AbstractEntityAdapter.php
+++ b/application/src/Api/Adapter/AbstractEntityAdapter.php
@@ -121,20 +121,21 @@ public function buildBaseQuery(QueryBuilder $qb, array $query)
     {
         if (isset($query['id'])) {
             $ids = $query['id'];
-            if (is_string($ids) || is_int($ids)) {
+            if (is_int($ids)) {
+                $ids = [(string) $ids];
+            } elseif (is_string($ids)) {
                 // Account for comma-delimited IDs.
                 $ids = false === strpos($ids, ',') ? [$ids] : explode(',', $ids);
-            } elseif (!is_array($ids)) {
+            } elseif (is_array($ids)) {
+                $ids = array_map('strval', $ids);
+            } else {
                 // This is an invalid ID. Set to an empty array.
                 $ids = [];
             }
             // Exclude null and empty-string IDs. Previous resource-only version
             // used is_numeric, but we want this to be able to work for possible
             // string IDs also.
-            $ids = array_map('trim', $ids);
-            $ids = array_filter($ids, function ($id) {
-                return !($id === null || $id === '');
-            });
+            $ids = array_filter(array_map('trim', $ids), 'strlen');
             if ($ids) {
                 $qb->andWhere($qb->expr()->in(
                     'omeka_root.id',
diff --git a/application/src/Form/Element/ArrayTextarea.php b/application/src/Form/Element/ArrayTextarea.php
index 61414c2f2..16ec8f32a 100644
--- a/application/src/Form/Element/ArrayTextarea.php
+++ b/application/src/Form/Element/ArrayTextarea.php
@@ -121,7 +121,7 @@ protected function stringToList($string)
      */
     protected function fixEndOfLine($string)
     {
-        return str_replace(["\r\n", "\n\r", "\r"], ["\n", "\n", "\n"], $string);
+        return str_replace(["\r\n", "\n\r", "\r"], ["\n", "\n", "\n"], (string) $string);
     }
 
     /**
diff --git a/application/src/View/Helper/SearchFilters.php b/application/src/View/Helper/SearchFilters.php
index 3928501d8..aa928dc94 100644
--- a/application/src/View/Helper/SearchFilters.php
+++ b/application/src/View/Helper/SearchFilters.php
@@ -218,16 +218,19 @@ public function __invoke($partialName = null, array $query = null)
 
                     case 'id':
                         $filterLabel = $translate('ID');
+                        // Avoid a deprecated issue, so convert ids as string.
                         $ids = $value;
-                        if (is_string($ids) || is_int($ids)) {
-                            $ids = false === strpos($ids, ',') ? [$ids] : explode(',', $ids);
-                        } elseif (!is_array($ids)) {
+                        if (is_int($ids)) {
+                            $ids = [(string) $ids];
+                        } elseif (is_string($ids)) {
+                            $ids = strpos($ids, ',') === false ? [$ids] : explode(',', $ids);
+                        } elseif (is_array($ids)) {
+                            $ids = array_map('strval', $ids);
+                        } else {
                             $ids = [];
                         }
                         $ids = array_map('trim', $ids);
-                        $ids = array_filter($ids, function ($id) {
-                            return !($id === null || $id === '');
-                        });
+                        $ids = array_filter($ids, 'strlen');
                         $filters[$filterLabel][] = implode(', ', $ids);
                         break;
                 }