diff --git a/src/Data/ECI.php b/src/Data/ECI.php
index daeba6981..1ca8c78bc 100644
--- a/src/Data/ECI.php
+++ b/src/Data/ECI.php
@@ -19,7 +19,7 @@ use chillerlan\QRCode\Common\{BitBuffer, Mode};
  *
  * Please note that you have to take care for the correct data encoding when adding with QRCode::add*Segment()
  */
-class ECI extends QRDataModeAbstract{
+final class ECI extends QRDataModeAbstract{
 
 	public const CP437                 = 0;  // Code page 437, DOS Latin US
 	public const ISO_IEC_8859_1_GLI    = 1;  // GLI encoding with characters 0 to 127 identical to ISO/IEC 646 and characters 128 to 255 identical to ISO 8859-1
diff --git a/src/Data/QRData.php b/src/Data/QRData.php
index 28ed1ad76..c02d50812 100644
--- a/src/Data/QRData.php
+++ b/src/Data/QRData.php
@@ -21,7 +21,7 @@ use function range, sprintf;
 /**
  * Processes the binary data and maps it on a matrix which is then being returned
  */
-class QRData{
+final class QRData{
 
 	/**
 	 * the options instance