Swagger UI does not render OpenAPI Definitions

[madduci]

Hello

I have a Spring 3.4.3 Application that has as dependencies both

• springdoc-openapi-starter-webmvc-api 2.8.5
• springdoc-openapi-starter-webmvc-ui 2.8.5

The UI is available at the address /swagger-ui/index.html, but i receive the following error:

Unable to render this definition

The provided definition does not specify a valid version field.

Please indicate a valid Swagger or OpenAPI version field. Supported version fields are swagger: "2.0" and those that match openapi: 3.0.n (for example, openapi: 3.0.0).

At the address /v3/api-docs i can see the OpenAPI Definition, which uses the Version 3.1.0:

{ "openapi":"3.1.0","info":{"title":"OpenAPI definition","version":"v0"}, .. }

To Reproduce
Steps to reproduce the behavior:

• SpringBoot 3.4.3 Project with Actuator and SpringDoc enabled
• Java 21 Temurin Runtime
• SpringDoc 2.8.5 Modules: springdoc-openapi-starter-webmvc-api and springdoc-openapi-starter-webmvc-ui
• The expected OpenAPI definition is working correctly (Version 3.1.0 of OpenAPI), saying openapi: 3.1.0
• Accessing /swagger-ui/index.html, an Error saying that The provided definition does not specify a valid version field. is shown

Expected behavior

• The Swagger UI should render the generated OpenAPI Definition

Screenshots

Swagger UI:

OpenAPI Definition:

[petergphillips]

We're using Spring Boot 3.4.3 and springdoc-openapi-starter-webmvc-ui 2.8.5 in all our projects and Swagger UI renders our documentation perfectly okay. Our /v3/api-docs starts with

{
  "openapi": "3.1.0",

too. I would therefore guess there is another factor here causing the problem.

[madduci]

This relates to

#2266

i could fix it by setting the Swagger UI Webjar to 5.20.0