diff --git a/modules/openapi-generator/src/main/resources/typescript-axios/modelGeneric.mustache b/modules/openapi-generator/src/main/resources/typescript-axios/modelGeneric.mustache
index 3aa462ea3a8..ddb8faf42dd 100644
--- a/modules/openapi-generator/src/main/resources/typescript-axios/modelGeneric.mustache
+++ b/modules/openapi-generator/src/main/resources/typescript-axios/modelGeneric.mustache
@@ -14,7 +14,7 @@ export interface {{classname}} {{#parent}}extends {{{parent}}} {{/parent}}{
      * @type {{=<% %>=}}{<%&datatype%>}<%={{ }}=%>
      * @memberof {{classname}}
      */
-    {{name}}{{^required}}?{{/required}}: {{#isEnum}}{{{datatypeWithEnum}}}{{/isEnum}}{{^isEnum}}{{{dataType}}}{{/isEnum}};
+    {{name}}{{^required}}?{{/required}}: {{#isEnum}}{{{datatypeWithEnum}}}{{/isEnum}}{{^isEnum}}{{{dataType}}}{{#isNullable}} | null{{/isNullable}}{{/isEnum}};
 {{/vars}}
 }{{#hasEnums}}
 
diff --git a/samples/client/petstore/typescript-axios/builds/default/.openapi-generator/VERSION b/samples/client/petstore/typescript-axios/builds/default/.openapi-generator/VERSION
index a6527129083..afa63656064 100644
--- a/samples/client/petstore/typescript-axios/builds/default/.openapi-generator/VERSION
+++ b/samples/client/petstore/typescript-axios/builds/default/.openapi-generator/VERSION
@@ -1 +1 @@
-3.3.2-SNAPSHOT
\ No newline at end of file
+4.0.0-SNAPSHOT
\ No newline at end of file
diff --git a/samples/client/petstore/typescript-axios/builds/es6-target/.openapi-generator/VERSION b/samples/client/petstore/typescript-axios/builds/es6-target/.openapi-generator/VERSION
index a6527129083..afa63656064 100644
--- a/samples/client/petstore/typescript-axios/builds/es6-target/.openapi-generator/VERSION
+++ b/samples/client/petstore/typescript-axios/builds/es6-target/.openapi-generator/VERSION
@@ -1 +1 @@
-3.3.2-SNAPSHOT
\ No newline at end of file
+4.0.0-SNAPSHOT
\ No newline at end of file
diff --git a/samples/client/petstore/typescript-axios/builds/with-interfaces/.openapi-generator/VERSION b/samples/client/petstore/typescript-axios/builds/with-interfaces/.openapi-generator/VERSION
index a6527129083..afa63656064 100644
--- a/samples/client/petstore/typescript-axios/builds/with-interfaces/.openapi-generator/VERSION
+++ b/samples/client/petstore/typescript-axios/builds/with-interfaces/.openapi-generator/VERSION
@@ -1 +1 @@
-3.3.2-SNAPSHOT
\ No newline at end of file
+4.0.0-SNAPSHOT
\ No newline at end of file
diff --git a/samples/client/petstore/typescript-axios/builds/with-npm-version/.openapi-generator/VERSION b/samples/client/petstore/typescript-axios/builds/with-npm-version/.openapi-generator/VERSION
index a6527129083..afa63656064 100644
--- a/samples/client/petstore/typescript-axios/builds/with-npm-version/.openapi-generator/VERSION
+++ b/samples/client/petstore/typescript-axios/builds/with-npm-version/.openapi-generator/VERSION
@@ -1 +1 @@
-3.3.2-SNAPSHOT
\ No newline at end of file
+4.0.0-SNAPSHOT
\ No newline at end of file