diff --git a/library/src/main/java/com/pengrad/telegrambot/model/chatbackground/BackgroundFill.java b/library/src/main/java/com/pengrad/telegrambot/model/chatbackground/BackgroundFill.java
index b7820600..6744ac35 100644
--- a/library/src/main/java/com/pengrad/telegrambot/model/chatbackground/BackgroundFill.java
+++ b/library/src/main/java/com/pengrad/telegrambot/model/chatbackground/BackgroundFill.java
@@ -2,7 +2,7 @@
 
 import java.util.Objects;
 
-public abstract class BackgroundFill {
+public class BackgroundFill {
 
     private final String type;
 
diff --git a/library/src/main/java/com/pengrad/telegrambot/model/chatbackground/BackgroundType.java b/library/src/main/java/com/pengrad/telegrambot/model/chatbackground/BackgroundType.java
index a04cd3be..bc00799b 100644
--- a/library/src/main/java/com/pengrad/telegrambot/model/chatbackground/BackgroundType.java
+++ b/library/src/main/java/com/pengrad/telegrambot/model/chatbackground/BackgroundType.java
@@ -2,7 +2,7 @@
 
 import java.util.Objects;
 
-public abstract class BackgroundType {
+public class BackgroundType {
 
     private final String type;
 
diff --git a/library/src/main/java/com/pengrad/telegrambot/model/chatboost/source/ChatBoostSource.java b/library/src/main/java/com/pengrad/telegrambot/model/chatboost/source/ChatBoostSource.java
index cf733082..eecd3e25 100644
--- a/library/src/main/java/com/pengrad/telegrambot/model/chatboost/source/ChatBoostSource.java
+++ b/library/src/main/java/com/pengrad/telegrambot/model/chatboost/source/ChatBoostSource.java
@@ -12,6 +12,13 @@ public class ChatBoostSource implements Serializable {
     protected String source;
     protected User user;
 
+    ChatBoostSource() {
+    }
+
+    public ChatBoostSource(String source) {
+        this.source = source;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o) return true;
diff --git a/library/src/main/java/com/pengrad/telegrambot/model/paidmedia/PaidMedia.java b/library/src/main/java/com/pengrad/telegrambot/model/paidmedia/PaidMedia.java
index 5d8a4271..3f3a7781 100644
--- a/library/src/main/java/com/pengrad/telegrambot/model/paidmedia/PaidMedia.java
+++ b/library/src/main/java/com/pengrad/telegrambot/model/paidmedia/PaidMedia.java
@@ -3,7 +3,7 @@
 import java.io.Serializable;
 import java.util.Objects;
 
-public abstract class PaidMedia implements Serializable {
+public class PaidMedia implements Serializable {
 
     private final static long serialVersionUID = 0L;
 
diff --git a/library/src/main/java/com/pengrad/telegrambot/model/reaction/ReactionType.java b/library/src/main/java/com/pengrad/telegrambot/model/reaction/ReactionType.java
index 93150887..3d5ff9f0 100644
--- a/library/src/main/java/com/pengrad/telegrambot/model/reaction/ReactionType.java
+++ b/library/src/main/java/com/pengrad/telegrambot/model/reaction/ReactionType.java
@@ -1,8 +1,10 @@
 package com.pengrad.telegrambot.model.reaction;
 
+import java.io.Serializable;
 import java.util.Objects;
 
-public abstract class ReactionType {
+public class ReactionType implements Serializable {
+    private final static long serialVersionUID = 0L;
 
     private final String type;
 
@@ -30,7 +32,7 @@ public int hashCode() {
     @Override
     public String toString() {
         return "ReactionType{" +
-            "type='" + type + '\'' +
-            '}';
+                "type='" + type + '\'' +
+                '}';
     }
 }
diff --git a/library/src/main/java/com/pengrad/telegrambot/model/stars/partner/TransactionPartner.java b/library/src/main/java/com/pengrad/telegrambot/model/stars/partner/TransactionPartner.java
index b7628461..75ab042f 100644
--- a/library/src/main/java/com/pengrad/telegrambot/model/stars/partner/TransactionPartner.java
+++ b/library/src/main/java/com/pengrad/telegrambot/model/stars/partner/TransactionPartner.java
@@ -3,7 +3,7 @@
 import java.io.Serializable;
 import java.util.Objects;
 
-public abstract class TransactionPartner implements Serializable {
+public class TransactionPartner implements Serializable {
 
     private final static long serialVersionUID = 0L;
 
diff --git a/library/src/main/java/com/pengrad/telegrambot/model/stars/withdrawal/RevenueWithdrawalState.java b/library/src/main/java/com/pengrad/telegrambot/model/stars/withdrawal/RevenueWithdrawalState.java
index 09e0ee71..ee5aefd7 100644
--- a/library/src/main/java/com/pengrad/telegrambot/model/stars/withdrawal/RevenueWithdrawalState.java
+++ b/library/src/main/java/com/pengrad/telegrambot/model/stars/withdrawal/RevenueWithdrawalState.java
@@ -1,17 +1,15 @@
 package com.pengrad.telegrambot.model.stars.withdrawal;
 
-import com.pengrad.telegrambot.model.chatbackground.BackgroundFill;
-
 import java.io.Serializable;
 import java.util.Objects;
 
-public abstract class RevenueWithdrawalState implements Serializable {
+public class RevenueWithdrawalState implements Serializable {
 
     private final static long serialVersionUID = 0L;
 
     private String type = "unknown";
 
-    protected RevenueWithdrawalState(String type) {
+    public RevenueWithdrawalState(String type) {
         this.type = type;
     }
 
diff --git a/library/src/main/java/com/pengrad/telegrambot/utility/gson/BackgroundFillAdapter.java b/library/src/main/java/com/pengrad/telegrambot/utility/gson/BackgroundFillAdapter.java
index 8ebe2123..6c3bba90 100644
--- a/library/src/main/java/com/pengrad/telegrambot/utility/gson/BackgroundFillAdapter.java
+++ b/library/src/main/java/com/pengrad/telegrambot/utility/gson/BackgroundFillAdapter.java
@@ -13,7 +13,8 @@ public class BackgroundFillAdapter implements JsonDeserializer<BackgroundFill> {
     @Override
     public BackgroundFill deserialize(JsonElement element, Type type, JsonDeserializationContext context) throws JsonParseException {
         JsonObject object = element.getAsJsonObject();
-        String discriminator = object.getAsJsonPrimitive("type").getAsString();
+        JsonPrimitive primitive = object.getAsJsonPrimitive("type");
+        String discriminator = primitive != null ? primitive.getAsString() : "unknown";
 
         if (BackgroundFillSolid.TYPE.equals(discriminator)) {
             return context.deserialize(object, BackgroundFillSolid.class);
@@ -23,6 +24,6 @@ public BackgroundFill deserialize(JsonElement element, Type type, JsonDeserializ
             return context.deserialize(object, BackgroundFillFreeformGradient.class);
         }
 
-        return context.deserialize(object, BackgroundFill.class);
+        return new BackgroundFill(discriminator);
     }
 }
diff --git a/library/src/main/java/com/pengrad/telegrambot/utility/gson/BackgroundTypeAdapter.java b/library/src/main/java/com/pengrad/telegrambot/utility/gson/BackgroundTypeAdapter.java
index cf0100ab..bfb8af8a 100644
--- a/library/src/main/java/com/pengrad/telegrambot/utility/gson/BackgroundTypeAdapter.java
+++ b/library/src/main/java/com/pengrad/telegrambot/utility/gson/BackgroundTypeAdapter.java
@@ -14,7 +14,8 @@ public class BackgroundTypeAdapter implements JsonDeserializer<BackgroundType> {
     @Override
     public BackgroundType deserialize(JsonElement element, Type type, JsonDeserializationContext context) throws JsonParseException {
         JsonObject object = element.getAsJsonObject();
-        String discriminator = object.getAsJsonPrimitive("type").getAsString();
+        JsonPrimitive primitive = object.getAsJsonPrimitive("type");
+        String discriminator = primitive != null ? primitive.getAsString() : "unknown";
 
         if (BackgroundTypeFill.TYPE.equals(discriminator)) {
             return context.deserialize(object, BackgroundTypeFill.class);
@@ -26,6 +27,6 @@ public BackgroundType deserialize(JsonElement element, Type type, JsonDeserializ
             return context.deserialize(object, BackgroundTypeChatTheme.class);
         }
 
-        return context.deserialize(object, BackgroundType.class);
+        return new BackgroundType(discriminator);
     }
 }
diff --git a/library/src/main/java/com/pengrad/telegrambot/utility/gson/ChatBoostSourceTypeAdapter.java b/library/src/main/java/com/pengrad/telegrambot/utility/gson/ChatBoostSourceTypeAdapter.java
index 72a8cb4b..290e1857 100644
--- a/library/src/main/java/com/pengrad/telegrambot/utility/gson/ChatBoostSourceTypeAdapter.java
+++ b/library/src/main/java/com/pengrad/telegrambot/utility/gson/ChatBoostSourceTypeAdapter.java
@@ -13,7 +13,8 @@ public class ChatBoostSourceTypeAdapter implements JsonDeserializer<ChatBoostSou
     @Override
     public ChatBoostSource deserialize(JsonElement element, Type type, JsonDeserializationContext context) throws JsonParseException {
         JsonObject object = element.getAsJsonObject();
-        String discriminator = object.getAsJsonPrimitive("source").getAsString();
+        JsonPrimitive primitive = object.getAsJsonPrimitive("source");
+        String discriminator = primitive != null ? primitive.getAsString() : "unknown";
 
         if (ChatBoostSourceGiftCode.CHAT_BOOST_TYPE.equals(discriminator)) {
             return context.deserialize(object, ChatBoostSourceGiftCode.class);
@@ -23,6 +24,6 @@ public ChatBoostSource deserialize(JsonElement element, Type type, JsonDeseriali
             return context.deserialize(object, ChatBoostSourcePremium.class);
         }
 
-        return context.deserialize(object, ChatBoostSource.class);
+        return new ChatBoostSource(discriminator);
     }
 }
diff --git a/library/src/main/java/com/pengrad/telegrambot/utility/gson/MaybeInaccessibleMessageTypeAdapter.java b/library/src/main/java/com/pengrad/telegrambot/utility/gson/MaybeInaccessibleMessageTypeAdapter.java
index f8d359f2..4b9eb4fc 100644
--- a/library/src/main/java/com/pengrad/telegrambot/utility/gson/MaybeInaccessibleMessageTypeAdapter.java
+++ b/library/src/main/java/com/pengrad/telegrambot/utility/gson/MaybeInaccessibleMessageTypeAdapter.java
@@ -14,7 +14,7 @@ public MaybeInaccessibleMessage deserialize(JsonElement element, Type type, Json
         JsonObject object = element.getAsJsonObject();
         JsonPrimitive discriminator = object.getAsJsonPrimitive("date");
 
-        if (!discriminator.isJsonNull() && discriminator.getAsInt() != InaccessibleMessage.INACCESSIBLE_MESSAGE_DATE) {
+        if (discriminator != null && !discriminator.isJsonNull() && discriminator.getAsInt() != InaccessibleMessage.INACCESSIBLE_MESSAGE_DATE) {
             return context.deserialize(object, Message.class);
         } else {
             return context.deserialize(object, InaccessibleMessage.class);
diff --git a/library/src/main/java/com/pengrad/telegrambot/utility/gson/MessageOriginTypeAdapter.java b/library/src/main/java/com/pengrad/telegrambot/utility/gson/MessageOriginTypeAdapter.java
index 41ea690e..190210ea 100644
--- a/library/src/main/java/com/pengrad/telegrambot/utility/gson/MessageOriginTypeAdapter.java
+++ b/library/src/main/java/com/pengrad/telegrambot/utility/gson/MessageOriginTypeAdapter.java
@@ -10,7 +10,8 @@ public class MessageOriginTypeAdapter implements JsonDeserializer<MessageOrigin>
     @Override
     public MessageOrigin deserialize(JsonElement element, Type type, JsonDeserializationContext context) throws JsonParseException {
         JsonObject object = element.getAsJsonObject();
-        String discriminator = object.getAsJsonPrimitive("type").getAsString();
+        JsonPrimitive primitive = object.getAsJsonPrimitive("type");
+        String discriminator = primitive != null ? primitive.getAsString() : "unknown";
 
         if (MessageOriginChannel.MESSAGE_ORIGIN_TYPE.equals(discriminator)) {
             return context.deserialize(object, MessageOriginChannel.class);
@@ -22,6 +23,6 @@ public MessageOrigin deserialize(JsonElement element, Type type, JsonDeserializa
             return context.deserialize(object, MessageOriginUser.class);
         }
 
-        return context.deserialize(object, MessageOrigin.class);
+        return new MessageOrigin(discriminator);
     }
 }
diff --git a/library/src/main/java/com/pengrad/telegrambot/utility/gson/PaidMediaTypeAdapter.java b/library/src/main/java/com/pengrad/telegrambot/utility/gson/PaidMediaTypeAdapter.java
index c99b39c4..968a3b7f 100644
--- a/library/src/main/java/com/pengrad/telegrambot/utility/gson/PaidMediaTypeAdapter.java
+++ b/library/src/main/java/com/pengrad/telegrambot/utility/gson/PaidMediaTypeAdapter.java
@@ -13,7 +13,8 @@ public class PaidMediaTypeAdapter implements JsonDeserializer<PaidMedia> {
     @Override
     public PaidMedia deserialize(JsonElement element, Type type, JsonDeserializationContext context) throws JsonParseException {
         JsonObject object = element.getAsJsonObject();
-        String discriminator = object.getAsJsonPrimitive("type").getAsString();
+        JsonPrimitive primitive = object.getAsJsonPrimitive("type");
+        String discriminator = primitive != null ? primitive.getAsString() : "unknown";
 
         if (PaidMediaPreview.TYPE.equals(discriminator)) {
             return context.deserialize(object, PaidMediaPreview.class);
@@ -23,6 +24,6 @@ public PaidMedia deserialize(JsonElement element, Type type, JsonDeserialization
             return context.deserialize(object, PaidMediaVideo.class);
         }
 
-        return context.deserialize(object, PaidMedia.class);
+        return new PaidMedia(discriminator);
     }
 }
diff --git a/library/src/main/java/com/pengrad/telegrambot/utility/gson/ReactionTypeAdapter.java b/library/src/main/java/com/pengrad/telegrambot/utility/gson/ReactionTypeAdapter.java
index 69aff521..a175ff89 100644
--- a/library/src/main/java/com/pengrad/telegrambot/utility/gson/ReactionTypeAdapter.java
+++ b/library/src/main/java/com/pengrad/telegrambot/utility/gson/ReactionTypeAdapter.java
@@ -12,7 +12,8 @@ public class ReactionTypeAdapter implements JsonDeserializer<ReactionType> {
     @Override
     public ReactionType deserialize(JsonElement element, Type type, JsonDeserializationContext context) throws JsonParseException {
         JsonObject object = element.getAsJsonObject();
-        String discriminator = object.getAsJsonPrimitive("type").getAsString();
+        JsonPrimitive primitive = object.getAsJsonPrimitive("type");
+        String discriminator = primitive != null ? primitive.getAsString() : "unknown";
 
         if (ReactionTypeEmoji.EMOJI_TYPE.equals(discriminator)) {
             return context.deserialize(object, ReactionTypeEmoji.class);
@@ -20,6 +21,6 @@ public ReactionType deserialize(JsonElement element, Type type, JsonDeserializat
             return context.deserialize(object, ReactionTypeCustomEmoji.class);
         }
 
-        return context.deserialize(object, ReactionType.class);
+        return new ReactionType(discriminator);
     }
 }
diff --git a/library/src/main/java/com/pengrad/telegrambot/utility/gson/RevenueWithdrawalStateTypeAdapter.java b/library/src/main/java/com/pengrad/telegrambot/utility/gson/RevenueWithdrawalStateTypeAdapter.java
index a5376fad..93893de9 100644
--- a/library/src/main/java/com/pengrad/telegrambot/utility/gson/RevenueWithdrawalStateTypeAdapter.java
+++ b/library/src/main/java/com/pengrad/telegrambot/utility/gson/RevenueWithdrawalStateTypeAdapter.java
@@ -13,7 +13,8 @@ public class RevenueWithdrawalStateTypeAdapter implements JsonDeserializer<Reven
     @Override
     public RevenueWithdrawalState deserialize(JsonElement element, Type type, JsonDeserializationContext context) throws JsonParseException {
         JsonObject object = element.getAsJsonObject();
-        String discriminator = object.getAsJsonPrimitive("type").getAsString();
+        JsonPrimitive primitive = object.getAsJsonPrimitive("type");
+        String discriminator = primitive != null ? primitive.getAsString() : "unknown";
 
         if (RevenueWithdrawalStatePending.TYPE.equals(discriminator)) {
             return context.deserialize(object, RevenueWithdrawalStatePending.class);
@@ -23,6 +24,6 @@ public RevenueWithdrawalState deserialize(JsonElement element, Type type, JsonDe
             return context.deserialize(object, RevenueWithdrawalStateFailed.class);
         }
 
-        return context.deserialize(object, RevenueWithdrawalState.class);
+        return new RevenueWithdrawalState(discriminator);
     }
 }
diff --git a/library/src/main/java/com/pengrad/telegrambot/utility/gson/TransactionPartnerTypeAdapter.java b/library/src/main/java/com/pengrad/telegrambot/utility/gson/TransactionPartnerTypeAdapter.java
index 75bd171b..036aff36 100644
--- a/library/src/main/java/com/pengrad/telegrambot/utility/gson/TransactionPartnerTypeAdapter.java
+++ b/library/src/main/java/com/pengrad/telegrambot/utility/gson/TransactionPartnerTypeAdapter.java
@@ -14,7 +14,8 @@ public class TransactionPartnerTypeAdapter implements JsonDeserializer<Transacti
     @Override
     public TransactionPartner deserialize(JsonElement element, Type type, JsonDeserializationContext context) throws JsonParseException {
         JsonObject object = element.getAsJsonObject();
-        String discriminator = object.getAsJsonPrimitive("type").getAsString();
+        JsonPrimitive primitive = object.getAsJsonPrimitive("type");
+        String discriminator = primitive != null ? primitive.getAsString() : "unknown";
 
         if (TransactionPartnerUser.TYPE.equals(discriminator)) {
             return context.deserialize(object, TransactionPartnerUser.class);
@@ -26,6 +27,6 @@ public TransactionPartner deserialize(JsonElement element, Type type, JsonDeseri
             return context.deserialize(object, TransactionPartnerOther.class);
         }
 
-        return context.deserialize(object, TransactionPartner.class);
+        return new TransactionPartner(discriminator);
     }
 }
diff --git a/library/src/test/java/com/pengrad/telegrambot/GsonAdaptersTest.kt b/library/src/test/java/com/pengrad/telegrambot/GsonAdaptersTest.kt
new file mode 100644
index 00000000..9099da80
--- /dev/null
+++ b/library/src/test/java/com/pengrad/telegrambot/GsonAdaptersTest.kt
@@ -0,0 +1,23 @@
+package com.pengrad.telegrambot
+
+import com.google.gson.JsonDeserializer
+import com.pengrad.telegrambot.utility.BotUtils.GSON
+import org.junit.Assert.assertNotNull
+import org.junit.Test
+import org.reflections.Reflections
+import java.lang.reflect.ParameterizedType
+
+
+class GsonAdaptersTest {
+
+    @Test
+    fun `all adapters fallback to base class`() {
+        val reflections = Reflections(TelegramBot::class.java.getPackage().name)
+        val adapters = reflections.getSubTypesOf(JsonDeserializer::class.java)
+        val types = adapters.map { (it.genericInterfaces[0] as ParameterizedType).actualTypeArguments[0] }
+        types.forEach {
+            assertNotNull(it.typeName, GSON.fromJson("{}", it))
+        }
+    }
+
+}
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
index 26934497..65a12516 100644
--- a/pom.xml
+++ b/pom.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
   <!-- This module was also published with a richer model, Gradle metadata,  -->
   <!-- which should be used instead. Do not delete the following line which  -->