diff --git a/matrix-sdk-android/src/androidTest/java/org/matrix/android/sdk/internal/crypto/verification/qrcode/QrCodeTest.kt b/matrix-sdk-android/src/androidTest/java/org/matrix/android/sdk/internal/crypto/verification/qrcode/QrCodeTest.kt
index ee604fc9ab..76bf6dc040 100644
--- a/matrix-sdk-android/src/androidTest/java/org/matrix/android/sdk/internal/crypto/verification/qrcode/QrCodeTest.kt
+++ b/matrix-sdk-android/src/androidTest/java/org/matrix/android/sdk/internal/crypto/verification/qrcode/QrCodeTest.kt
@@ -226,12 +226,12 @@ class QrCodeTest : InstrumentedTest {
 
     private fun checkHeader(byteArray: ByteArray) {
         // MATRIX
-        byteArray[0] shouldBeEqualTo 'M'.toByte()
-        byteArray[1] shouldBeEqualTo 'A'.toByte()
-        byteArray[2] shouldBeEqualTo 'T'.toByte()
-        byteArray[3] shouldBeEqualTo 'R'.toByte()
-        byteArray[4] shouldBeEqualTo 'I'.toByte()
-        byteArray[5] shouldBeEqualTo 'X'.toByte()
+        byteArray[0] shouldBeEqualTo 'M'.code.toByte()
+        byteArray[1] shouldBeEqualTo 'A'.code.toByte()
+        byteArray[2] shouldBeEqualTo 'T'.code.toByte()
+        byteArray[3] shouldBeEqualTo 'R'.code.toByte()
+        byteArray[4] shouldBeEqualTo 'I'.code.toByte()
+        byteArray[5] shouldBeEqualTo 'X'.code.toByte()
 
         // Version
         byteArray[6] shouldBeEqualTo 2
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/verification/qrcode/Extensions.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/verification/qrcode/Extensions.kt
index 6bc3483e65..76e88442b6 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/verification/qrcode/Extensions.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/verification/qrcode/Extensions.kt
@@ -48,7 +48,7 @@ fun QrCodeData.toEncodedString(): String {
 
     // TransactionId
     transactionId.forEach {
-        result += it.toByte()
+        result += it.code.toByte()
     }
 
     // Keys