diff --git a/docs/30_Usage.md b/docs/30_Usage.md
index c16e5c0ffe7273233d336bd865f490af2b866806..fc6ae8da08ecd552a2a1dbe08dcfd87972855412 100644
--- a/docs/30_Usage.md
+++ b/docs/30_Usage.md
@@ -85,6 +85,7 @@ The binary could stop and exit with non zero exitcode.
 | 4        | Given Ini file does not exist
 | 5        | Given Ini file cannot be parsed
 | 6        | Ini value `params=` is no JSON
+| 7        | The key 'function' is not set in the given check. It defines the check function to call.
 
 ### appmonitor-client class
 
diff --git a/src/amcli.php b/src/amcli.php
index 73f3e354ff4684f9c2b78decf9006ee243a6e278..f796f6d9ac8bd782c7d00455f4f84174d3cc933e 100755
--- a/src/amcli.php
+++ b/src/amcli.php
@@ -18,6 +18,8 @@
  * 2025-03-09  v0.4    more colors in output of debug and help
  * 2025-03-14  v0.5    add build infos
  * 2025-03-14  v0.6    add meta tags, check count+visual; add _json2array()
+ * 2025-03-17  v0.7    update help
+ * 2025-03-17  v0.8    check missing 'function' in check. get php client version
  * ======================================================================
  */
 
@@ -26,7 +28,8 @@ $argc = $_SERVER['argc'];
 $argv = $_SERVER['argv'];
 
 $FLAG_DEBUG = 0;
-$VERSION = "0.7";
+$VERSION = "0.8";
+$PHPCLIENTVERSION = "not-detected";
 
 $AMCLI_BUILD_DATE = "never";
 
@@ -100,18 +103,18 @@ function _wd($s): void
  */
 function _showHelp(): void
 {
-    global $VERSION;
+    global $VERSION, $PHPCLIENTVERSION;
     $_self = str_replace('.php', '', basename(__FILE__));
     echo "
    _____ _____ __                   _____         _ _           
   |     |     |  |      ___ ___ ___|     |___ ___|_| |_ ___ ___ 
   |-   -| | | |  |__   | .'| . | . | | | | . |   | |  _| . |  _|
   |_____|_|_|_|_____|  |__,|  _|  _|_|_|_|___|_|_|_|_| |___|_|  
-                           |_| |_|                              
-                                               \e[1mCLI client v$VERSION\e[0m
+                           |_| |_|             \e[1mCLI client v$VERSION\e[0m
+
 
 This client performs appmonitor checks and puts the results as JSON to stdout.
-It contains all checks that are available in the PHP appmonitor client.
+It contains all checks that are available in the PHP appmonitor client v$PHPCLIENTVERSION.
 You can use the compiled binary to monitor any non PHP webapp without 
 implementing the checks for your programming language.
 
@@ -201,6 +204,7 @@ _wd("CLI ARGS: " . print_r($ARGS ?? [], 1));
 _wd("Initializing appmonitor class");
 
 $oMonitor = new appmonitor();
+$PHPCLIENTVERSION = $oMonitor->getVersion();
 $sPreSpace = " - ";
 
 // show version
@@ -219,7 +223,7 @@ if (isset($ARGS['-b']) || isset($ARGS['--buildinfos'])) {
     echo "amcli v$VERSION (".PHP_OS.")\n\n";
     echo "Build date: $AMCLI_BUILD_DATE\n";
     echo "\n";
-    echo "Compiled with PHP ".PHP_VERSION."\n";
+    echo "Compiled PHP client v$PHPCLIENTVERSION with PHP ".PHP_VERSION."\n";
     echo "Including these modules:\n";
     $sModules="    ";
     $i=0;
@@ -298,6 +302,7 @@ $aIni['notifications']['slack']=_json2array($aIni['notifications']['slack'] ?? n
 _set("setHost", $aIni['meta']['host'] ?? null);
 _set("setWebsite", $aIni['meta']['website'] ?? null);
 _set("setTtl", $aIni['meta']['ttl'] ?? null);
+_set("setVersion", "amcli-$VERSION-using");
 
 foreach ($aIni['meta']['tags'] ?? [] as $sValue) {
     _set("addTag", $sValue);
@@ -322,16 +327,20 @@ foreach ($aChecks as $sKey => $aCheck) {
     $aParams = _json2array($aCheck['params'] ?? []);
     if (!is_array($aParams)) {
         echo "❌ ERROR: key 'params' for check [$sKey] must be \n- a hash or\n- valid JSON\n- not set\n";
-        echo "Value in $inifile: $aCheck[params]\n";
+        echo "Value in $inifile: $aCheck[params]??[]\n";
         echo "Try to use multiple lines 'params[<KEY>]=<VALUE>'.\n";
         exit(6);
     }
 
+    if(!isset($aCheck['function'])){
+        echo "❌ ERROR: Missing key 'function' in check [$sKey].\n";
+        exit(7);
+    }
     $aAddCheck = [
         "name" => $aCheck['name'] ?? $sKey,
         "description" => $aCheck['description'] ?? "",
         "check" => [
-            "function" => $aCheck['function'],
+            "function" => $aCheck['function'] ?? "not set",
             "params" => $aParams,
         ],
     ];