Cannot configure Http 2 in Embedded Tomcat with Spring Boot 1.5.17

Question

I am trying to configure HTTP 2 for my Spring Boot project that runs in the Embedded Tomcat Server 8.5.34 but I am unable to do so. I have followed this SO Thread but couldn't achieve that. My Server starts and is working fine but it works in HTTP 1.1 even after configuring for HTTP 2. I have configured my project to run with a self signed certificate and those setting are in the application.properties file. Below is my configuration file. Please help.

@Configuration
public class ConnectorConfig {

    @Bean
    public EmbeddedServletContainerFactory servletContainer() {
        TomcatEmbeddedServletContainerFactory tomcat = new TomcatEmbeddedServletContainerFactory() {
            @Override
            protected void postProcessContext(Context context) {
                SecurityConstraint securityConstraint = new SecurityConstraint();
                securityConstraint.setUserConstraint("CONFIDENTIAL");
                SecurityCollection collection = new SecurityCollection();
                collection.addPattern("/*");
                securityConstraint.addCollection(collection);
                context.addConstraint(securityConstraint);
            }
        };

        tomcat.addAdditionalTomcatConnectors(getHttpConnector());

        // the following line isn't working
        // tomcat.addConnectorCustomizers((TomcatConnectorCustomizer) connector -> connector.addUpgradeProtocol(new Http2Protocol()));
        return tomcat;
    }


    @Bean // not working
    public EmbeddedServletContainerCustomizer tomcatCustomizer() {
        return (container) -> {
            if (container instanceof TomcatEmbeddedServletContainerFactory) {
                ((TomcatEmbeddedServletContainerFactory) container)
                        .addConnectorCustomizers((connector) -> connector.addUpgradeProtocol(new Http2Protocol()));
            }
        };
    }

    private Connector getHttpConnector() {
        Connector connector = new Connector(TomcatEmbeddedServletContainerFactory.DEFAULT_PROTOCOL);
        connector.setScheme("http");
        connector.setPort(8080);
        connector.setSecure(false);
        connector.setRedirectPort(9000);

        // the following line isn't working
        // connector.addUpgradeProtocol(new Http2Protocol());
        return connector;
    }
}