diff --git a/.travis.yml b/.travis.yml
index 2bb53086..3d8e26f0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,6 @@
 sudo: required
 language: node_js
 node_js:
-- '15'
 - '14'
 - '12'
 - '10'
diff --git a/src/middlewares/parsers/request.schema.preprocessor.ts b/src/middlewares/parsers/request.schema.preprocessor.ts
index b25cbb24..4a216dbb 100644
--- a/src/middlewares/parsers/request.schema.preprocessor.ts
+++ b/src/middlewares/parsers/request.schema.preprocessor.ts
@@ -82,6 +82,9 @@ export class RequestSchemaPreprocessor {
           schema.required = required
             .slice(0, index)
             .concat(required.slice(index + 1));
+          if (schema.required.length === 0) {
+            delete schema.required;
+          }
         }
       }
     };
diff --git a/test/oneof.readonly.spec.ts b/test/oneof.readonly.spec.ts
index 83aad5ed..da0fe5bb 100644
--- a/test/oneof.readonly.spec.ts
+++ b/test/oneof.readonly.spec.ts
@@ -14,6 +14,9 @@ describe('one.of readonly', () => {
       app.use(
         express
           .Router()
+          .post(`${app.basePath}/any_of_one_required`, (req, res) =>
+            res.status(200).json({ success: true }),
+          )
           .post(`${app.basePath}/any_of`, (req, res) =>
             res.status(200).json({ success: true }),
           )
@@ -46,6 +49,13 @@ describe('one.of readonly', () => {
         expect(error.message).to.include('to one of the allowed values: C, D');
       }));
 
+  it('post type anyof without providing the single required readonly property should pass', async () =>
+    request(app)
+      .post(`${app.basePath}/one_of`)
+      .send({ type: 'C' }) // do not provide id
+      .set('Content-Type', 'application/json')
+      .expect(200));
+
   it('post type oneOf (without readonly id) should pass', async () =>
     request(app)
       .post(`${app.basePath}/one_of`)
diff --git a/test/oneof.readonly.yaml b/test/oneof.readonly.yaml
index 7f7590d2..c4574421 100644
--- a/test/oneof.readonly.yaml
+++ b/test/oneof.readonly.yaml
@@ -6,6 +6,23 @@ info:
 servers:
   - url: /v1
 paths:
+  /any_of_one_required:
+    post:
+      requestBody:
+        content:
+            application/json:
+              schema:
+                anyOf:
+                  - $ref: '#/components/schemas/subE'
+                  - $ref: '#/components/schemas/subF'
+                discriminator:
+                  propertyName: type
+                  mapping:
+                    A: '#/components/schemas/subE'
+                    B: '#/components/schemas/subF'
+      responses:
+          200:
+            description: successful operation
   /any_of:
     post:
       requestBody:
@@ -57,6 +74,18 @@ components:
         - id
         - type  
 
+    one_required:
+      type: object
+      properties:
+        id:
+          readOnly: true
+          type: string
+        type:
+          type: string
+          enum: [A, B]          
+      required:
+        - id
+
     subA:
       allOf:
         - $ref: '#/components/schemas/common'
@@ -91,4 +120,12 @@ components:
               enum: [C, D]          
           required:
             - id
-            - type  
\ No newline at end of file
+            - type  
+
+    subE:
+      allOf:
+        - $ref: '#/components/schemas/one_required'
+
+    subF:
+      allOf:
+        - $ref: '#/components/schemas/one_required'
\ No newline at end of file