diff --git a/include/netlicensing/converters.h b/include/netlicensing/converters.h
index 3947d8e..628e918 100644
--- a/include/netlicensing/converters.h
+++ b/include/netlicensing/converters.h
@@ -109,7 +109,12 @@ namespace netlicensing {
   inline parameters_type toParametersList<Token>(Token value) {
     parameters_type params = toParametersList<BaseEntity>(value);
     params.push_back(std::make_pair(VENDOR_NUMBER, value.getVendorNumber()));
-    params.push_back(std::make_pair(EXPIRATION_TIME, value.getExpirationTime().toString()));
+
+    const std::string expirationTime = value.getExpirationTime().toString();
+    if (!expirationTime.empty()) {
+        params.push_back(std::make_pair(EXPIRATION_TIME, expirationTime));
+    }
+
     params.push_back(std::make_pair(TOKEN_TYPE, tokenTypeToString(value.getTokenType())));
     return params;
   }
diff --git a/include/netlicensing/country.h b/include/netlicensing/country.h
index 5f08336..d2d02e8 100644
--- a/include/netlicensing/country.h
+++ b/include/netlicensing/country.h
@@ -63,6 +63,11 @@ namespace netlicensing {
       ss << "isEu: " << isEu << ", ";
       ss << "code: " << code << ", ";
       ss << "vatPercent: " << vatPercent;
+
+      for (const auto& pair : getProperties()) {
+          ss << ", " << pair.first << ": " << pair.second.toString();
+      }
+
       ss << "]";
       return ss.str();
     }
diff --git a/include/netlicensing/license.h b/include/netlicensing/license.h
index 29a87f5..ea06524 100644
--- a/include/netlicensing/license.h
+++ b/include/netlicensing/license.h
@@ -90,6 +90,11 @@ namespace netlicensing {
       ss << HIDDEN << ": " << hidden.toString() << ", ";
       ss << LICENSEE_NUMBER << ": " << licenseeNumber << ", ";
       ss << LICENSE_TEMPLATE_NUMBER << ": " << licenseTemplateNumber;
+
+      for (const auto& pair : getProperties()) {
+          ss << ", " << pair.first << ": " << pair.second.toString();
+      }
+
       ss << "]";
       return ss.str();
     }
diff --git a/include/netlicensing/license_template.h b/include/netlicensing/license_template.h
index e5472de..775029e 100644
--- a/include/netlicensing/license_template.h
+++ b/include/netlicensing/license_template.h
@@ -111,6 +111,11 @@ namespace netlicensing {
       ss << AUTOMATIC << ": " << automatic.toString() << ", ";
       ss << HIDDEN << ": " << hidden.toString() << ", ";
       ss << HIDE_LICENSES << ": " << hideLicenses.toString();
+
+      for (const auto& pair : getProperties()) {
+          ss << ", " << pair.first << ": " << pair.second.toString();
+      }
+
       ss << "]";
       return ss.str();
     }
diff --git a/include/netlicensing/licensee.h b/include/netlicensing/licensee.h
index 8395a78..dff04e1 100644
--- a/include/netlicensing/licensee.h
+++ b/include/netlicensing/licensee.h
@@ -41,6 +41,11 @@ namespace netlicensing {
       ss << NUMBER << ": " << number << ", ";
       ss << ACTIVE << ": " << active.toString() << ", ";
       ss << PRODUCT_NUMBER << ": " << productNumber;
+
+      for (const auto& pair : getProperties()) {
+          ss << ", " << pair.first << ": " << pair.second.toString();
+      }
+
       ss << "]";
       return ss.str();
     }
diff --git a/include/netlicensing/mapper.h b/include/netlicensing/mapper.h
index ca355d8..6e90066 100644
--- a/include/netlicensing/mapper.h
+++ b/include/netlicensing/mapper.h
@@ -103,6 +103,8 @@ namespace netlicensing {
         item_i.setDescription(value);
       } else if (key == LICENSING_INFO) {
         item_i.setLicensingInfo(value);
+      } else {
+        item_i.addProperty(key, value);
       }
     }
 
@@ -138,6 +140,8 @@ namespace netlicensing {
           item_i.setLicensingModel(value);
         } else if (key == PRODUCT_NUMBER) {
           item_i.setProductNumber(value);
+        } else {
+          item_i.addProperty(key, value);
         }
     }
   };
@@ -171,6 +175,8 @@ namespace netlicensing {
         item_i.setHidden((value == "true"?true:false));
       } else if (key == HIDE_LICENSES) {
         item_i.setHideLicenses((value == "true"?true:false));
+      } else {
+        item_i.addProperty(key, value);
       }
     }
   };
@@ -192,6 +198,8 @@ namespace netlicensing {
         item_i.setName(value);
       } else if (key == PRODUCT_NUMBER) {
         item_i.setProductNumber(value);
+      } else {
+        item_i.addProperty(key, value);
       }
     }
   };
@@ -221,6 +229,8 @@ namespace netlicensing {
         item_i.setLicenseeNumber(value);
       } else if (key == LICENSE_TEMPLATE_NUMBER) {
         item_i.setLicenseTemplateNumber(value);
+      } else {
+        item_i.addProperty(key, value);
       }
     }
   };
@@ -242,6 +252,8 @@ namespace netlicensing {
         item_i.setName(value);
       } else if (key == "vatPercent") {
         item_i.setVatPercent(value);
+      } else {
+        item_i.addProperty(key, value);
       }
     }
   };
@@ -312,6 +324,8 @@ namespace netlicensing {
         item_i.setExpirationTime(value);
       } else if (key == TOKEN_TYPE) {
         item_i.setTokenType(stringToTokenType(value));
+      } else {
+        item_i.addProperty(key, value);
       }
     }
   };
@@ -343,6 +357,8 @@ namespace netlicensing {
         item_i.setDateCreated(value);
       } else if (key == DATE_CLOSED) {
         item_i.setDateClosed(value);
+      } else {
+        item_i.addProperty(key, value);
       }
     }
   };
diff --git a/include/netlicensing/product.h b/include/netlicensing/product.h
index 2fda65f..7f0b284 100644
--- a/include/netlicensing/product.h
+++ b/include/netlicensing/product.h
@@ -171,6 +171,11 @@ namespace netlicensing {
         ss << LICENSEE_AUTO_CREATE << ": " << licenseeAutoCreate << ", ";
         ss << DESCRIPTION << ": " << description << ", ";
         ss << LICENSING_INFO << ": " << licensingInfo;
+
+        for (const auto& pair : getProperties()) {
+            ss << ", " << pair.first << ": " << pair.second.toString();
+        }
+
         ss << "]";
       return ss.str();
     }
diff --git a/include/netlicensing/product_module.h b/include/netlicensing/product_module.h
index 388d215..4af53fb 100644
--- a/include/netlicensing/product_module.h
+++ b/include/netlicensing/product_module.h
@@ -55,6 +55,11 @@ namespace netlicensing {
       ss << ACTIVE << ": " << active.toString() << ", ";
       ss << LICENSING_MODEL << ": " << licensingModel << ", ";
       ss << PRODUCT_NUMBER << ": " << productNumber;
+
+      for (const auto& pair : getProperties()) {
+          ss << ", " << pair.first << ": " << pair.second.toString();
+      }
+
       ss << "]";
       return ss.str();
     }
diff --git a/include/netlicensing/token.h b/include/netlicensing/token.h
index e3100d1..e1c9420 100644
--- a/include/netlicensing/token.h
+++ b/include/netlicensing/token.h
@@ -55,6 +55,11 @@ namespace netlicensing {
       ss << VENDOR_NUMBER << ": " << vendorNumber << ", ";
       ss << EXPIRATION_TIME << ": " << expirationTime << ", ";
       ss << TOKEN_TYPE << ": " << tokenType;
+
+      for (const auto& pair : getProperties()) {
+          ss << ", " << pair.first << ": " << pair.second.toString();
+      }
+
       ss << "]";
       return ss.str();
     }
diff --git a/include/netlicensing/transaction.h b/include/netlicensing/transaction.h
index c5f411d..66e61aa 100644
--- a/include/netlicensing/transaction.h
+++ b/include/netlicensing/transaction.h
@@ -100,6 +100,11 @@ namespace netlicensing {
       ss << CURRENCY << ": " << currency << ", ";
       ss << DATE_CREATED << ": " << dateCreated << ", ";
       ss << DATE_CLOSED << ": " << dateClosed;
+
+      for (const auto& pair : getProperties()) {
+          ss << ", " << pair.first << ": " << pair.second.toString();
+      }
+
       ss << "]";
       return ss.str();
     }