diff --git a/www/admin/class_test.strings.php b/www/admin/class_test.strings.php
index 4e08b2fa..23b26075 100644
--- a/www/admin/class_test.strings.php
+++ b/www/admin/class_test.strings.php
@@ -21,8 +21,6 @@ require 'config.php';
 $LOG_FILE_ID = 'classTest-string';
 ob_end_flush();
 
-use CoreLibs\Convert\Byte;
-
 $log = new CoreLibs\Debug\Logging([
 	'log_folder' => BASE . LOG,
 	'file_id' => $LOG_FILE_ID,
diff --git a/www/lib/CoreLibs/Combined/DateTime.php b/www/lib/CoreLibs/Combined/DateTime.php
index 728f5e0e..56db0dba 100644
--- a/www/lib/CoreLibs/Combined/DateTime.php
+++ b/www/lib/CoreLibs/Combined/DateTime.php
@@ -209,7 +209,7 @@ class DateTime
 		if ($isodow < 1 || $isodow > 7) {
 			return $long ? 'Invalid' : 'Inv';
 		}
-		return date($long ? 'l' : 'D', strtotime("Sunday +{$isodow} days"));
+		return date($long ? 'l' : 'D', strtotime("Sunday +{$isodow} days") ?: null);
 	}
 
 	/**
@@ -224,7 +224,7 @@ class DateTime
 		if (!self::checkDate($date)) {
 			return $long ? 'Invalid' : 'Inv';
 		}
-		return date($long ? 'l' : 'D', strtotime($date));
+		return date($long ? 'l' : 'D', strtotime($date) ?: null);
 	}
 
 	/**
@@ -238,7 +238,7 @@ class DateTime
 		if (!self::checkDate($date)) {
 			return -1;
 		}
-		return (int)date('N', strtotime($date));
+		return (int)date('N', strtotime($date) ?: null);
 	}
 
 	/**
diff --git a/www/lib/CoreLibs/Convert/Strings.php b/www/lib/CoreLibs/Convert/Strings.php
index a820fcdc..09a99756 100644
--- a/www/lib/CoreLibs/Convert/Strings.php
+++ b/www/lib/CoreLibs/Convert/Strings.php
@@ -29,7 +29,7 @@ class Strings
 	public static function splitFormatString(
 		string $value,
 		string $split_format,
-		string $split_charcters = '-'
+		string $split_characters = '-'
 	): string {
 		// abort if split format is empty
 		if (empty($split_format)) {
@@ -45,7 +45,7 @@ class Strings
 		// }
 		$split_list = preg_split(
 			// allowed split characters
-			"/([" . $split_charcters . "]{1})/",
+			"/([" . $split_characters . "]{1})/",
 			$split_format,
 			-1,
 			PREG_SPLIT_DELIM_CAPTURE
@@ -74,7 +74,7 @@ class Strings
 			$out .= $last_split . substr($value, $pos);
 		}
 		// if last is not alphanumeric remove, remove
-		if (!strcspn(substr($out, -1, 1), $split_charcters)) {
+		if (!strcspn(substr($out, -1, 1), $split_characters)) {
 			$out = substr($out, 0, -1);
 		}
 		// overwrite only if out is set