diff --git a/boot.php b/boot.php
index eda8a4037d..c6f7b1e20d 100644
--- a/boot.php
+++ b/boot.php
@@ -742,7 +742,7 @@ function run_update_function($x)
 		// delete the config entry to try again.
 
 		$t = Config::get('database', 'update_' . $x);
-		if ($t !== false) {
+		if (!is_null($t)) {
 			return false;
 		}
 		Config::set('database', 'update_' . $x, time());
diff --git a/include/nav.php b/include/nav.php
index f2bf161f9e..58ec150e7a 100644
--- a/include/nav.php
+++ b/include/nav.php
@@ -209,7 +209,7 @@ function nav_info(App $a)
 
 	// Provide a banner/logo/whatever
 	$banner = Config::get('system', 'banner');
-	if ($banner === false) {
+	if (is_null($banner)) {
 		$banner = '<a href="https://friendi.ca"><img id="logo-img" src="images/friendica-32.png" alt="logo" /></a><span id="logo-text"><a href="https://friendi.ca">Friendica</a></span>';
 	}
 
diff --git a/include/network.php b/include/network.php
index 52e3409573..06649554b0 100644
--- a/include/network.php
+++ b/include/network.php
@@ -126,6 +126,7 @@ function z_fetch_url($url, $binary = false, &$redirects = 0, $opts = array())
 	if (x($opts, 'timeout')) {
 		@curl_setopt($ch, CURLOPT_TIMEOUT, $opts['timeout']);
 	} else {
+		// if Config::get returns null, intval will be 0 which will also evaluate to false
 		$curl_time = intval(Config::get('system', 'curl_timeout'));
 		@curl_setopt($ch, CURLOPT_TIMEOUT, (($curl_time !== false) ? $curl_time : 60));
 	}
@@ -302,6 +303,7 @@ function post_url($url, $params, $headers = null, &$redirects = 0, $timeout = 0)
 	if (intval($timeout)) {
 		curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);
 	} else {
+		// if Config::get returns null, intval will be 0 which will also evaluate to false
 		$curl_time = intval(Config::get('system', 'curl_timeout'));
 		curl_setopt($ch, CURLOPT_TIMEOUT, (($curl_time !== false) ? $curl_time : 60));
 	}
diff --git a/src/Content/Feature.php b/src/Content/Feature.php
index 864c07a0d8..f17b649eef 100644
--- a/src/Content/Feature.php
+++ b/src/Content/Feature.php
@@ -23,13 +23,15 @@ class Feature
 	{
 		$x = Config::get('feature_lock', $feature, false);
 
-		if ($x === false) {
+		if (is_null($x)) {
 			$x = PConfig::get($uid, 'feature', $feature, false);
 		}
-		if ($x === false) {
+
+		if (is_null($x)) {
 			$x = Config::get('feature', $feature, false);
 		}
-		if ($x === false) {
+
+		if (is_null($x)) {
 			$x = self::getDefault($feature);
 		}
 
diff --git a/src/Network/FKOAuthDataStore.php b/src/Network/FKOAuthDataStore.php
index 126f140bdf..d7fa145189 100644
--- a/src/Network/FKOAuthDataStore.php
+++ b/src/Network/FKOAuthDataStore.php
@@ -171,7 +171,7 @@ class FKOAuthDataStore extends OAuthDataStore
 		dba::delete('tokens', array('id' => $token->key));
 
 
-		if (!is_null($ret) && $uverifier !== false) {
+		if (!is_null($ret) && !is_null($uverifier)) {
 			Config::delete("oauth", $verifier);
 		}
 
diff --git a/src/Worker/OnePoll.php b/src/Worker/OnePoll.php
index c1fb5350c3..c3528b623e 100644
--- a/src/Worker/OnePoll.php
+++ b/src/Worker/OnePoll.php
@@ -92,7 +92,7 @@ Class OnePoll
 
 		if ($contact['subhub']) {
 			$poll_interval = Config::get('system', 'pushpoll_frequency');
-			$contact['priority'] = (($poll_interval !== false) ? intval($poll_interval) : 3);
+			$contact['priority'] = ((!is_null($poll_interval)) ? intval($poll_interval) : 3);
 			$hub_update = false;
 
 			if (datetime_convert('UTC', 'UTC', 'now') > datetime_convert('UTC', 'UTC', $t . " + 1 day")) {
diff --git a/view/theme/vier/theme.php b/view/theme/vier/theme.php
index a8654f743b..0f81200890 100644
--- a/view/theme/vier/theme.php
+++ b/view/theme/vier/theme.php
@@ -110,13 +110,13 @@ EOT;
 function get_vier_config($key, $default = false, $admin = false) {
 	if (local_user() && !$admin) {
 		$result = PConfig::get(local_user(), "vier", $key);
-		if ($result !== false) {
+		if (!is_null($result)) {
 			return $result;
 		}
 	}
 
 	$result = Config::get("vier", $key);
-	if ($result !== false) {
+	if (!is_null($result)) {
 		return $result;
 	}