diff --git a/README.md b/README.md
index e00cc483..42f5d89f 100644
--- a/README.md
+++ b/README.md
@@ -60,7 +60,7 @@ As commented above, they both could be used at the same time, setting a double
 <plugin>
   <groupId>com.sngular</groupId>
   <artifactId>scs-multiapi-maven-plugin</artifactId>
-  <version>5.3.4</version>
+  <version>5.3.5</version>
   <executions>
     <execution>
       <id>asyncapi</id>
@@ -114,7 +114,7 @@ Apply the plugin in the `build.gradle` file and invoke the task.
 ```groovy
 plugins {
   id "java"
-  id "com.sngular.scs-multiapi-gradle-plugin' version '5.3.4"
+  id "com.sngular.scs-multiapi-gradle-plugin' version '5.3.5"
 
   openapimodel {
 
@@ -153,7 +153,7 @@ which the plugin is designed.
 <plugin>
   <groupId>com.sngular</groupId>
   <artifactId>scs-multiapi-maven-plugin</artifactId>
-  <version>5.3.4</version>
+  <version>5.3.5</version>
   <executions>
     <execution>
       <phase>generate-sources</phase>
@@ -584,7 +584,7 @@ file. Here is an example of a basic configuration:
 <plugin>
   <groupId>com.sngular</groupId>
   <artifactId>scs-multiapi-maven-plugin</artifactId>
-  <version>5.3.4</version>
+  <version>5.3.5</version>
   <executions>
     <execution>
       <goals>
diff --git a/multiapi-engine/pom.xml b/multiapi-engine/pom.xml
index 2ec7ae92..e2345f0a 100644
--- a/multiapi-engine/pom.xml
+++ b/multiapi-engine/pom.xml
@@ -4,7 +4,7 @@
 
   <groupId>com.sngular</groupId>
   <artifactId>multiapi-engine</artifactId>
-  <version>5.3.4</version>
+  <version>5.3.5</version>
   <packaging>jar</packaging>
 
   <properties>
diff --git a/multiapi-engine/src/main/java/com/sngular/api/generator/plugin/asyncapi/util/MapperUtil.java b/multiapi-engine/src/main/java/com/sngular/api/generator/plugin/asyncapi/util/MapperUtil.java
index ce68ef48..cf536e62 100644
--- a/multiapi-engine/src/main/java/com/sngular/api/generator/plugin/asyncapi/util/MapperUtil.java
+++ b/multiapi-engine/src/main/java/com/sngular/api/generator/plugin/asyncapi/util/MapperUtil.java
@@ -64,17 +64,17 @@ public static String getSimpleType(final JsonNode schema, final String prefix, f
         type = formatTypeOfString(format, useTimeType);
       } else if (NUMBER.equalsIgnoreCase(type)) {
         if (FLOAT.equalsIgnoreCase(format)) {
-          type = FLOAT;
+          type = StringUtils.capitalize(FLOAT);
         } else if (DOUBLE.equalsIgnoreCase(format)) {
-          type = DOUBLE;
+          type = StringUtils.capitalize(DOUBLE);
         } else {
-          type = BIG_DECIMAL;
+          type = StringUtils.capitalize(BIG_DECIMAL);
         }
       } else if (INTEGER.equalsIgnoreCase(type)) {
         if (INT_64.equalsIgnoreCase(format)) {
-          type = LONG;
+          type = StringUtils.capitalize(LONG);
         } else {
-          type = INTEGER;
+          type = StringUtils.capitalize(INTEGER);
         }
       }
     } else if (schema.has(REF)) {
diff --git a/multiapi-engine/src/main/java/com/sngular/api/generator/plugin/asyncapi/util/ReferenceProcessor.java b/multiapi-engine/src/main/java/com/sngular/api/generator/plugin/asyncapi/util/ReferenceProcessor.java
index 07c902c7..29d831f0 100644
--- a/multiapi-engine/src/main/java/com/sngular/api/generator/plugin/asyncapi/util/ReferenceProcessor.java
+++ b/multiapi-engine/src/main/java/com/sngular/api/generator/plugin/asyncapi/util/ReferenceProcessor.java
@@ -19,6 +19,8 @@ public final class ReferenceProcessor {
 
   private static final String YML = "yml";
 
+  private static final String YAML = "yaml";
+
   private static final String REF = "$ref";
 
   private static final String AVSC = "avsc";
@@ -78,7 +80,7 @@ private JsonNode solveRef(final FileLocation ymlParent, final String[] path, fin
     final String filePath = pathToFile[0];
     JsonNode returnNode = null;
 
-    if (filePath.endsWith(YML) || filePath.endsWith(JSON)) {
+    if (filePath.endsWith(YML) || filePath.endsWith(JSON) || filePath.endsWith(YAML)) {
       final JsonNode node = ApiTool.nodeFromFile(ymlParent, filePath, FactoryTypeEnum.YML);
       if (node.findValue(path[path.length - 2]).has(path[path.length - 1])) {
         returnNode = node.findValue(path[path.length - 2]).get(path[path.length - 1]);
diff --git a/multiapi-engine/src/main/java/com/sngular/api/generator/plugin/openapi/utils/MapperPathUtil.java b/multiapi-engine/src/main/java/com/sngular/api/generator/plugin/openapi/utils/MapperPathUtil.java
index 75298ca2..e8e87ed3 100644
--- a/multiapi-engine/src/main/java/com/sngular/api/generator/plugin/openapi/utils/MapperPathUtil.java
+++ b/multiapi-engine/src/main/java/com/sngular/api/generator/plugin/openapi/utils/MapperPathUtil.java
@@ -130,6 +130,7 @@ private static List<OperationObject> mapOperationObject(final SpecFile specFile,
   private static OperationObject createOperation(
       final JsonNode operation, final String operationType, final SpecFile specFile, final GlobalObject globalObject,
       final List<String> operationIdList, final Path baseDir) {
+    Objects.requireNonNull(operation.get("tags"), "Tags element is required");
     return OperationObject.builder()
                           .operationId(mapOperationId(getOperationId(operation), operationIdList))
                           .operationType(operationType)
diff --git a/multiapi-engine/src/test/resources/asyncapigenerator/testCustomValidators/assets/DataDTO.java b/multiapi-engine/src/test/resources/asyncapigenerator/testCustomValidators/assets/DataDTO.java
index 5f9d8059..11efb65f 100644
--- a/multiapi-engine/src/test/resources/asyncapigenerator/testCustomValidators/assets/DataDTO.java
+++ b/multiapi-engine/src/test/resources/asyncapigenerator/testCustomValidators/assets/DataDTO.java
@@ -41,7 +41,7 @@ public class DataDTO {
   @MinItems(minimum = 5)
   @UniqueItems
   @NotNull
-  private final List<integer> test = new ArrayList<integer>();
+  private final List<Integer> test = new ArrayList<Integer>();
 
   private DataDTO(DataDTOBuilder builder) {
     this.clientId = builder.clientId;
@@ -65,7 +65,7 @@ public static class DataDTOBuilder {
 
     private String flightNumber;
 
-    private List<integer> test = new ArrayList<integer>();
+    private List<Integer> test = new ArrayList<Integer>();
 
     public DataDTO.DataDTOBuilder clientId(Integer clientId) {
       this.clientId = clientId;
@@ -82,14 +82,14 @@ public DataDTO.DataDTOBuilder flightNumber(String flightNumber) {
       return this;
     }
 
-    public DataDTO.DataDTOBuilder test(List<integer> test) {
+    public DataDTO.DataDTOBuilder test(List<Integer> test) {
       if (!test.isEmpty()) {
         this.test.addAll(test);
       }
       return this;
     }
 
-    public DataDTO.DataDTOBuilder test(integer test) {
+    public DataDTO.DataDTOBuilder test(Integer test) {
       if (test != null) {
         this.test.add(test);
       }
@@ -134,7 +134,7 @@ public String getFlightNumber() {
   * @return test
   */
   @Schema(name = "test", required = true)
-  public List<integer> getTest() {
+  public List<Integer> getTest() {
     return test;
   }
 
diff --git a/scs-multiapi-gradle-plugin/build.gradle b/scs-multiapi-gradle-plugin/build.gradle
index f40b0096..38acf355 100644
--- a/scs-multiapi-gradle-plugin/build.gradle
+++ b/scs-multiapi-gradle-plugin/build.gradle
@@ -20,7 +20,7 @@ repositories {
 }
 
 group = 'com.sngular'
-version = '5.3.4'
+version = '5.3.5'
 
 def SCSMultiApiPluginGroupId = group
 def SCSMultiApiPluginVersion = version
@@ -30,7 +30,7 @@ dependencies {
   shadow localGroovy()
   shadow gradleApi()
 
-  implementation 'com.sngular:multiapi-engine:5.3.4'
+  implementation 'com.sngular:multiapi-engine:5.3.5'
   testImplementation 'org.assertj:assertj-core:3.24.2'
   testImplementation 'com.puppycrawl.tools:checkstyle:10.12.3'
 }
@@ -98,7 +98,7 @@ testing {
 
     integrationTest(JvmTestSuite) {
       dependencies {
-        implementation 'com.sngular:scs-multiapi-gradle-plugin:5.3.4'
+        implementation 'com.sngular:scs-multiapi-gradle-plugin:5.3.5'
         implementation 'org.assertj:assertj-core:3.24.2'
       }
 
diff --git a/scs-multiapi-maven-plugin/pom.xml b/scs-multiapi-maven-plugin/pom.xml
index a05568b8..e554ee14 100644
--- a/scs-multiapi-maven-plugin/pom.xml
+++ b/scs-multiapi-maven-plugin/pom.xml
@@ -4,7 +4,7 @@
 
   <groupId>com.sngular</groupId>
   <artifactId>scs-multiapi-maven-plugin</artifactId>
-  <version>5.3.4</version>
+  <version>5.3.5</version>
   <packaging>maven-plugin</packaging>
 
   <name>AsyncApi - OpenApi Code Generator Maven Plugin</name>
@@ -243,7 +243,7 @@
     <dependency>
       <groupId>com.sngular</groupId>
       <artifactId>multiapi-engine</artifactId>
-      <version>5.3.4</version>
+      <version>5.3.5</version>
     </dependency>
     <dependency>
       <groupId>org.apache.maven</groupId>