diff --git a/bootstrap.php b/bootstrap.php
index db89437cf629d92d78321827e538dd95ef6ab1e9..05dc1c25010714f1cad1836471ac980719b3c61e 100644
--- a/bootstrap.php
+++ b/bootstrap.php
@@ -68,6 +68,6 @@ $config['maxLinesToRead'] = $row['maxLinesToRead'];
 
 $config['maxErrLinesToRead'] = $row['maxErrLinesToRead'];
 $config['maxLinesToWrite'] = $row['maxLinesToWrite'];
-$config['showTestRunnerDebugOutput'] = $row['showTestRunnerDebugOutput'] === 1;
+$config['showTestRunnerDebugOutput'] = $row['showTestRunnerDebugOutput'] === '1';
 
 return $config;
\ No newline at end of file
diff --git a/do_blackBoxTest_func.php b/do_blackBoxTest_func.php
index 08e127cb6374426529ed3d8822b24fed37f3c9f9..f91df7e46e61e992d3d4386a21ad4350dcd8498a 100644
--- a/do_blackBoxTest_func.php
+++ b/do_blackBoxTest_func.php
@@ -97,7 +97,7 @@ function do_blackBoxTest($mainFileNameWithExtension, $test, $fullWorkingDirPath,
     . ' "' . $maxErrLinesToRead . '"'                      # arg[11] max lines to read from the user program stderr (inclusive)
     . ' "' . $maxLinesToWrite . '"'                        # arg[12]  max lines to write to the user program (inclusive)
     . ' "' . $uniqueSessionId . '"'                        # arg[13] a unique session id
-    . ' "' . $showTestRunnerDebugOutput . '"'              # arg[14] showTestRunnerDebugOutput
+    . ' "' . ($showTestRunnerDebugOutput === TRUE ? 1 : 0) . '"'              # arg[14] showTestRunnerDebugOutput
 
     ;
 
diff --git a/do_compileTest_func.php b/do_compileTest_func.php
index 62adc336b499dde283b28791ee62dd2d7de26c87..b1ade84213f8857b2e9874b7708eaac96749779d 100644
--- a/do_compileTest_func.php
+++ b/do_compileTest_func.php
@@ -38,7 +38,7 @@ function do_compile($mainFileNameWithExtension, $fullWorkingDirPath, $compileCmd
         . ' "' . $compileCmd . '"'                              # arg[3] command to execute
         . ' "' . implode(',', $sourceFileExtensions) . '"'# arg[4] the source file extensions
         . ' "' . $uniqueSessionId . '"'                         # arg[5] a unique session id
-        . ' "' . $showTestRunnerDebugOutput . '"'              # arg[6] showTestRunnerDebugOutput
+        . ' "' . ($showTestRunnerDebugOutput === TRUE ? 1 : 0) . '"'              # arg[6] showTestRunnerDebugOutput
     ;
 
     exec($longCmd, $output, $return_var);
diff --git a/readme.md b/readme.md
index d68d2b7ffb20e8e4213e1ab68fe905f65f3be283..c08f0dfa974764c89d384b4e7467f51bea659cc7 100644
--- a/readme.md
+++ b/readme.md
@@ -368,7 +368,7 @@ A json object with the following properties (order does not matter)
   after the java executable (else the user program would be called with utf8 encoding but the test runner cannot handle UTF8)
   **also do not forget to correctly set the compile and exec commands in the PLang Table (add the -Dfile.encoding=UTF8 there too)!!!**
   
-* **showTestRunnerDebugOutput**: 0/1, 1: show some internal debug output from the test runner for debugging (sent back as a part of the test response) 
+* **showTestRunnerDebugOutput**: (int) 0/1, 1: show some internal debug output from the test runner for debugging (sent back as a part of the test response) 
 * **maxLinesToRead**: (int) the total (inclusive) number of lines to read from the user program (-x or 0 for unlimited)
 * **maxErrLinesToRead**: (int) the total (inclusive) number of lines to read from the user program error stream (stderr) (-x or 0 for unlimited)
 * **maxLinesToWrite**: (int) the total (inclusive) number of lines to write to the user program (-x or 0 for unlimited)