diff --git a/diaspora/diaspora.php b/diaspora/diaspora.php
index 1fe6fa12a..79c0aba2f 100644
--- a/diaspora/diaspora.php
+++ b/diaspora/diaspora.php
@@ -145,7 +145,7 @@ function diaspora_hook_fork(App $a, array &$b)
 	$post = $b['data'];
 
 	if ($post['deleted'] || $post['private'] || ($post['created'] !== $post['edited']) ||
-		!strstr($post['postopts'], 'diaspora') || ($post['parent'] != $post['id'])) {
+		!strstr($post['postopts'] ?? '', 'diaspora') || ($post['parent'] != $post['id'])) {
 		$b['execute'] = false;
 		return;
 	}
diff --git a/tumblr/tumblr.php b/tumblr/tumblr.php
index 281c58ac0..c3a5561f3 100644
--- a/tumblr/tumblr.php
+++ b/tumblr/tumblr.php
@@ -266,7 +266,7 @@ function tumblr_hook_fork(App $a, array &$b)
 	$post = $b['data'];
 
 	if ($post['deleted'] || $post['private'] || ($post['created'] !== $post['edited']) ||
-		!strstr($post['postopts'], 'tumblr') || ($post['parent'] != $post['id'])) {
+		!strstr($post['postopts'] ?? '', 'tumblr') || ($post['parent'] != $post['id'])) {
 		$b['execute'] = false;
 		return;
 	}
@@ -442,4 +442,3 @@ function tumblr_send(App $a, array &$b) {
 		}
 	}
 }
-
diff --git a/twitter/twitter.php b/twitter/twitter.php
index 54ccfa1eb..80ac14a6d 100644
--- a/twitter/twitter.php
+++ b/twitter/twitter.php
@@ -440,7 +440,7 @@ function twitter_hook_fork(App $a, array &$b)
 		return;
 	}
 
-	if (substr($post['app'], 0, 7) == 'Twitter') {
+	if (substr($post['app'] ?? '', 0, 7) == 'Twitter') {
 		DI::logger()->info('No Twitter app');
 		$b['execute'] = false;
 		return;
@@ -455,7 +455,7 @@ function twitter_hook_fork(App $a, array &$b)
 		}
 	} else {
 		// Comments are never exported when we don't import the twitter timeline
-		if (!strstr($post['postopts'], 'twitter') || ($post['parent'] != $post['id']) || $post['private']) {
+		if (!strstr($post['postopts'] ?? '', 'twitter') || ($post['parent'] != $post['id']) || $post['private']) {
 			DI::logger()->info('Comments are never exported when we don\'t import the twitter timeline');
 			$b['execute'] = false;
 			return;
@@ -1582,7 +1582,7 @@ function twitter_auto_follow(int $uid, object $data)
 			// We only probe on Mastodon style URL to reduce the number of unsuccessful probes
 			twitter_add_contact($url->expanded_url, strpos($url->expanded_url, '@'), $uid);
 		}
-	} 
+	}
 }
 
 /**
diff --git a/wppost/wppost.php b/wppost/wppost.php
index aa7adf5e9..be2461dd9 100644
--- a/wppost/wppost.php
+++ b/wppost/wppost.php
@@ -107,7 +107,7 @@ function wppost_hook_fork(App $a, array &$b)
 	$post = $b['data'];
 
 	if ($post['deleted'] || $post['private'] || ($post['created'] !== $post['edited']) ||
-		!strstr($post['postopts'], 'wppost') || ($post['parent'] != $post['id'])) {
+		!strstr($post['postopts'] ?? '', 'wppost') || ($post['parent'] != $post['id'])) {
 		$b['execute'] = false;
 		return;
 	}