diff --git a/pfsense_zbx.php b/pfsense_zbx.php
index 8a365b1..5975f50 100644
--- a/pfsense_zbx.php
+++ b/pfsense_zbx.php
@@ -1116,7 +1116,7 @@ function pfz_get_cert_date($valuekey){
     global $config;
     
     // Contains a list of refs that were revoked and should not be considered
-    $revoked_cert_refs;
+    $revoked_cert_refs = [];
     foreach ($config["crl"] as $crl) {
         foreach ($crl["cert"] as $revoked_cert) {
             $revoked_cert_refs[] = $revoked_cert["refid"];
@@ -1129,7 +1129,7 @@ function pfz_get_cert_date($valuekey){
                 case "validFrom.max":
                         foreach ($config[$cert_type] as $cert) {
                                 if ( ! in_array($cert['refid'], $revoked_cert_refs) ) {
-                                        $certinfo = openssl_x509_parse(base64_decode($cert[crt]));
+                                        $certinfo = openssl_x509_parse(base64_decode($cert["crt"]));
                                         if ($value == 0 or $value < $certinfo['validFrom_time_t']) $value = $certinfo['validFrom_time_t'];
                                 }
             		}
@@ -1137,7 +1137,7 @@ function pfz_get_cert_date($valuekey){
                 case "validTo.min":
                         foreach ($config[$cert_type] as $cert) {
                                 if ( ! in_array($cert['refid'], $revoked_cert_refs) ) {
-                                        $certinfo = openssl_x509_parse(base64_decode($cert[crt]));
+                                        $certinfo = openssl_x509_parse(base64_decode($cert["crt"]));
                                         if ($value == 0 or $value > $certinfo['validTo_time_t']) $value = $certinfo['validTo_time_t'];
                                 }
                         }
diff --git a/pfsense_zbx_rc.php b/pfsense_zbx_rc.php
index bd82c12..74dda34 100644
--- a/pfsense_zbx_rc.php
+++ b/pfsense_zbx_rc.php
@@ -135,8 +135,6 @@ const CARP_RES = [
 // Abstract undefined symbols and globals from code
 class PfEnv
 {
-    public const CRT = crt;
-
     public static function cfg()
     {
         global $config;
@@ -1063,7 +1061,7 @@ class Command
         $all_certs = Util::array_flatten($certs_and_cas);
 
         return Util::result(array_reduce($all_certs, function ($value, $certificate) use ($field) {
-            $cert_info = openssl_x509_parse(base64_decode($certificate[PfEnv::CRT]));
+            $cert_info = openssl_x509_parse(base64_decode($certificate["crt"]));
 
             if ($value == 0 || $value < $cert_info[$field]) {
                 return $cert_info[$field];