diff --git a/examples/example_052.php b/examples/example_052.php
index 9c07b23d..778c658d 100644
--- a/examples/example_052.php
+++ b/examples/example_052.php
@@ -77,8 +77,8 @@
 
 // set certificate file
 $certificate = file_get_contents("data/cert/PDF User.pem");
-$ca = "data/cert/Root CA Test.crt";
-$extracerts = getcwd()."/$ca";
+$issuer = "data/cert/Root CA Test.crt";
+$extracerts = file_get_contents($issuer);
 $crl = "data/cert/RootCATest.der.crl";
 
 // set additional information
@@ -89,18 +89,19 @@
 	'ContactInfo' => 'http://www.tcpdf.org',
 	);
 
-// set LTV setLtv($ocspURI=null, $crlURIorFILE=null, $issuerURIorFILE=null)
-// set null to skip ocsp or crl
-// set to empty or false will continue lookup in certificate attributes (Authority Info Access(AIA) and CRL Distribution Points(CDP))
+// set LTV setLtv($ocspURI=false, $crlURIorFILE=false, $issuerURIorFILE=false)
+// set false to skip ocsp or crl
+// set to empty or null will continue lookup in certificate attributes (Authority Info Access(AIA) and CRL Distribution Points(CDP))
 // skip both will result no LTV. Note that issuerURIorFILE cannot skipped. It will use given address/file location or lookup in cert AIA attributes if null.
 // dont give any parameter to lookup all address in cert attributes.
-$pdf->setLtv(null, $crl, $ca);
+$pdf->setLtv();
 
 // Set TSA server address
 $pdf->setTimeStamp('http://timestamp.apple.com/ts01');
 
 // set document signature
-$pdf->setSignature($certificate, $certificate, 'tcpdfdemo', $extracerts, 2, $info);
+// added digest algorithm in last arguments
+$pdf->setSignature($certificate, $certificate, 'tcpdfdemo', $extracerts, 2, $info, 'sha256');
 
 // set font. 'helvetica' MUST be used to avoid a PHP notice from PHP 7.4+
 $pdf->setFont('helvetica', '', 12);