diff --git a/src/blackmisc/simulation/aircraftmodellist.cpp b/src/blackmisc/simulation/aircraftmodellist.cpp
index 005a79896..fd272059b 100644
--- a/src/blackmisc/simulation/aircraftmodellist.cpp
+++ b/src/blackmisc/simulation/aircraftmodellist.cpp
@@ -977,7 +977,7 @@ namespace BlackMisc
             return json;
         }
 
-        void CAircraftModelList::convertFromMemoizedJson(const QJsonObject &json)
+        void CAircraftModelList::convertFromMemoizedJson(const QJsonObject &json, bool fallbackToConvertToJson)
         {
             clear();
             QJsonValue value = json.value("containerbase");
@@ -988,9 +988,25 @@ namespace BlackMisc
             const QJsonValue aircraftIcaos = json.value("aircraftIcaos");
             const QJsonValue liveries = json.value("liveries");
             const QJsonValue distributors = json.value("distributors");
-            if (aircraftIcaos.isUndefined()) { throw CJsonException("Missing 'aircraftIcaos'"); }
-            if (liveries.isUndefined()) { throw CJsonException("Missing 'liveries'"); }
-            if (distributors.isUndefined()) { throw CJsonException("Missing 'distributors'"); }
+
+            const bool undefAc = aircraftIcaos.isUndefined();
+            const bool undefLiv = liveries.isUndefined();
+            const bool undefDist = distributors.isUndefined();
+            const bool undefAll = undefAc && undefDist && undefLiv;
+
+            if (fallbackToConvertToJson && undefAll)
+            {
+                this->convertFromJson(json);
+                return;
+            }
+            else
+            {
+                if (undefAc)   { throw CJsonException("Missing 'aircraftIcaos'"); }
+                if (undefLiv)  { throw CJsonException("Missing 'liveries'"); }
+                if (undefDist) { throw CJsonException("Missing 'distributors'"); }
+            }
+
+            // convert
             {
                 CJsonScope scope("aircraftIcaos");
                 Q_UNUSED(scope);
diff --git a/src/blackmisc/simulation/aircraftmodellist.h b/src/blackmisc/simulation/aircraftmodellist.h
index 8d7a83f2f..66387ce5b 100644
--- a/src/blackmisc/simulation/aircraftmodellist.h
+++ b/src/blackmisc/simulation/aircraftmodellist.h
@@ -335,7 +335,7 @@ namespace BlackMisc
             QJsonObject toMemoizedJson() const;
 
             //! From compact JSON format
-            void convertFromMemoizedJson(const QJsonObject &json);
+            void convertFromMemoizedJson(const QJsonObject &json, bool fallbackToConvertToJson = false);
 
             //! To database JSON
             QJsonArray toDatabaseJson() const;
diff --git a/src/blackmisc/variant.cpp b/src/blackmisc/variant.cpp
index 7c8369cec..761f0aa35 100644
--- a/src/blackmisc/variant.cpp
+++ b/src/blackmisc/variant.cpp
@@ -194,7 +194,9 @@ namespace BlackMisc
                 {
                     CJsonScope scope("value");
                     m_v = QVariant(typeId, nullptr);
-                    meta->convertFromJson(value.toObject(), data());
+
+                    // this will call convertFromJson if there is no MemoizedJson
+                    meta->convertFromMemoizedJson(value.toObject(), data(), true);
                 }
                 else if (QMetaType::hasRegisteredConverterFunction(qMetaTypeId<QString>(), typeId))
                 {
@@ -253,7 +255,7 @@ namespace BlackMisc
         }
     }
 
-    void CVariant::convertFromMemoizedJson(const QJsonObject &json)
+    void CVariant::convertFromMemoizedJson(const QJsonObject &json, bool allowFallbackToJson)
     {
         QJsonValue typeValue = json.value("type");
         if (typeValue.isUndefined()) { throw CJsonException("Missing 'type'"); }
@@ -271,7 +273,7 @@ namespace BlackMisc
 
                 CJsonScope scope("value");
                 m_v = QVariant(typeId, nullptr);
-                meta->convertFromMemoizedJson(value.toObject(), data());
+                meta->convertFromMemoizedJson(value.toObject(), data(), allowFallbackToJson);
             }
             catch (const Private::CVariantException &ex)
             {
@@ -288,7 +290,7 @@ namespace BlackMisc
     {
         try
         {
-            convertFromMemoizedJson(json);
+            convertFromMemoizedJson(json, false);
         }
         catch (const CJsonException &ex)
         {
diff --git a/src/blackmisc/variant.h b/src/blackmisc/variant.h
index 850a982c5..98a38cf6e 100644
--- a/src/blackmisc/variant.h
+++ b/src/blackmisc/variant.h
@@ -286,7 +286,7 @@ namespace BlackMisc
         QJsonObject toMemoizedJson() const;
 
         //! From compact JSON format.
-        void convertFromMemoizedJson(const QJsonObject &json);
+        void convertFromMemoizedJson(const QJsonObject &json, bool allowFallbackToJson);
 
         //! Call convertFromMemoizedJson, catch any CJsonException that is thrown and return it as CStatusMessage.
         CStatusMessage convertFromMemoizedJsonNoThrow(const QJsonObject &json, const CLogCategoryList &categories, const QString &prefix);
diff --git a/src/blackmisc/variantmap.cpp b/src/blackmisc/variantmap.cpp
index 15c001901..9ae026ff6 100644
--- a/src/blackmisc/variantmap.cpp
+++ b/src/blackmisc/variantmap.cpp
@@ -86,7 +86,7 @@ namespace BlackMisc
             CJsonScope scope(key);
             Q_UNUSED(scope);
             CVariant value;
-            value.convertFromMemoizedJson(it.value().toObject());
+            value.convertFromMemoizedJson(it.value().toObject(), true);
             implementationOf(*this).insert(cend(), key, value);
         }
     }
@@ -101,7 +101,7 @@ namespace BlackMisc
             CJsonScope scope(key);
             Q_UNUSED(scope);
             CVariant var;
-            var.convertFromMemoizedJson(value.toObject());
+            var.convertFromMemoizedJson(value.toObject(), true);
             insert(key, var);
         }
     }
diff --git a/src/blackmisc/variantprivate.h b/src/blackmisc/variantprivate.h
index 88ed7eb83..79d8cdd72 100644
--- a/src/blackmisc/variantprivate.h
+++ b/src/blackmisc/variantprivate.h
@@ -47,7 +47,7 @@ namespace BlackMisc
             virtual QJsonObject toJson(const void *object) const = 0;
             virtual void convertFromJson(const QJsonObject &json, void *object) const = 0;
             virtual QJsonObject toMemoizedJson(const void *object) const = 0;
-            virtual void convertFromMemoizedJson(const QJsonObject &json, void *object) const = 0;
+            virtual void convertFromMemoizedJson(const QJsonObject &json, void *object, bool allowFallbackToJson) const = 0;
             virtual void unmarshall(const QDBusArgument &arg, void *object) const = 0;
             virtual uint getValueHash(const void *object) const = 0;
             virtual int getMetaTypeId() const = 0;
@@ -101,9 +101,9 @@ namespace BlackMisc
             static QJsonObject toMemoizedJson(const T &object, ...) { return toJson(object, 0); }
 
             template <typename T>
-            static void convertFromMemoizedJson(const QJsonObject &json, T &object, decltype(static_cast<void>(object.convertFromMemoizedJson(json)), 0)) { object.convertFromMemoizedJson(json); }
+            static void convertFromMemoizedJson(const QJsonObject &json, T &object, bool allowFallbackToJson, decltype(static_cast<void>(object.convertFromMemoizedJson(json, allowFallbackToJson)), 0)) { object.convertFromMemoizedJson(json, allowFallbackToJson); }
             template <typename T>
-            static void convertFromMemoizedJson(const QJsonObject &json, T &object, ...) { convertFromJson(json, object, 0); }
+            static void convertFromMemoizedJson(const QJsonObject &json, T &object, bool allowFallbackToJson, ...) { convertFromJson(json, object, 0); Q_UNUSED(allowFallbackToJson) }
 
             template <typename T>
             static uint getValueHash(const T &object, decltype(static_cast<void>(qHash(object)), 0)) { return qHash(object); }
@@ -113,7 +113,7 @@ namespace BlackMisc
             template <typename T>
             static int compareImpl(const T &lhs, const T &rhs, decltype(static_cast<void>(compare(lhs, rhs)), 0)) { return compare(lhs, rhs); }
             template <typename T>
-            static int compareImpl(const T &lhs, const T&, ...) { throw CVariantException(lhs, "compare"); }
+            static int compareImpl(const T &lhs, const T &, ...) { throw CVariantException(lhs, "compare"); }
 
             template <typename T>
             static void setPropertyByIndex(T &object, const CVariant &variant, const CPropertyIndex &index, decltype(static_cast<void>(object.setPropertyByIndex(index, variant)), 0)) { object.setPropertyByIndex(index, variant); }
@@ -136,7 +136,7 @@ namespace BlackMisc
             static bool equalsPropertyByIndex(const T &object, const CVariant &, const CPropertyIndex &, ...) { throw CVariantException(object, "equalsPropertyByIndex"); }
 
             template <typename T>
-            static void toIcon(const T &object, CIcon &o_icon, std::enable_if_t<! std::is_same<T, CVariant>::value, decltype(static_cast<void>(object.toIcon()), 0)>) { assign(o_icon, object.toIcon()); }
+            static void toIcon(const T &object, CIcon &o_icon, std::enable_if_t < ! std::is_same<T, CVariant>::value, decltype(static_cast<void>(object.toIcon()), 0) >) { assign(o_icon, object.toIcon()); }
             template <typename T>
             static void toIcon(const T &object, CIcon &, ...) { throw CVariantException(object, "toIcon"); }
         };
@@ -161,9 +161,9 @@ namespace BlackMisc
             {
                 return CValueObjectMetaInfoHelper::toMemoizedJson(cast(object), 0);
             }
-            virtual void convertFromMemoizedJson(const QJsonObject &json, void *object) const override
+            virtual void convertFromMemoizedJson(const QJsonObject &json, void *object, bool allowFallbackToJson) const override
             {
-                CValueObjectMetaInfoHelper::convertFromMemoizedJson(json, cast(object), 0);
+                CValueObjectMetaInfoHelper::convertFromMemoizedJson(json, cast(object), allowFallbackToJson, 0);
             }
             virtual void unmarshall(const QDBusArgument &arg, void *object) const override
             {