Instead of doing:

@Bean
Saml2AuthenticationRequestFactory authenticationRequestFactory() {
    OpenSaml4AuthenticationRequestFactory factory = new OpenSaml4AuthenticationRequestFactory();
	factory.setProtocolBinding("urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST")
	return factory;
@Bean
Saml2AuthenticationRequestResolver authenticationRequestResolver() {
	OpenSaml4AuthenticationRequestResolver reaolver = new OpenSaml4AuthenticationRequestResolver(registrations);
	resolver.setAuthnRequestCustomizer((context) -> context.getAuthnRequest()
            .setProtocolBinding("urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST"));
	return resolver;
In an early release, Saml2AuthenticationToken took several individual settings as constructor parameters.
This created a challenge each time a new parameter needed to be added.
Since most of these settings were part of RelyingPartyRegistration, a new constructor was added where a RelyingPartyRegistration could be provided, making the constructor more stable.
It also is valuable in that it more closely aligns with the design of OAuth2LoginAuthenticationToken.
Most applications do not construct this class directly since Saml2WebSsoAuthenticationFilter does.
However, in the event that your application constructs one, please change from:
new Saml2AuthenticationToken(saml2Response, registration.getSingleSignOnServiceLocation(),
    registration.getAssertingParty().getEntityId(), registration.getEntityId(), registration.getCredentials())
In an early release of Spring Security’s SAML support, there was some ambiguity on the meaning of certain RelyingPartyRegistration methods and their function.
As more capabilities were added to RelyingPartyRegistration, it became necessary to clarify this ambiguity by changing method names to ones that aligned with spec language.
The deprecated methods in RelyingPartyRegstration are removed.
To prepare for that, consider the following representative usage of RelyingPartyRegistration:
String idpEntityId = registration.getRemoteIdpEntityId();
String assertionConsumerServiceUrl = registration.getAssertionConsumerServiceUrlTemplate();
String idpWebSsoUrl = registration.getIdpWebSsoUrl();
String localEntityId = registration.getLocalEntityIdTemplate();
List<Saml2X509Credential> verifying = registration.getCredentials().stream()
        .filter(Saml2X509Credential::isSignatureVerficationCredential)
        .collect(Collectors.toList());
val idpEntityId: String = registration.getRemoteIdpEntityId()
val assertionConsumerServiceUrl: String = registration.getAssertionConsumerServiceUrlTemplate()
val idpWebSsoUrl: String = registration.getIdpWebSsoUrl()
val localEntityId: String = registration.getLocalEntityIdTemplate()
val verifying: List<Saml2X509Credential> = registration.getCredentials()
        .filter(Saml2X509Credential::isSignatureVerficationCredential)
String assertingPartyEntityId = registration.getAssertingPartyDetails().getEntityId();
String assertionConsumerServiceLocation = registration.getAssertionConsumerServiceLocation();
String singleSignOnServiceLocation = registration.getAssertingPartyDetails().getSingleSignOnServiceLocation();
String entityId = registration.getEntityId();
List<Saml2X509Credential> verifying = registration.getAssertingPartyDetails().getVerificationX509Credentials();
val assertingPartyEntityId: String = registration.getAssertingPartyDetails().getEntityId()
val assertionConsumerServiceLocation: String = registration.getAssertionConsumerServiceLocation()
val singleSignOnServiceLocation: String = registration.getAssertingPartyDetails().getSingleSignOnServiceLocation()
val entityId: String = registration.getEntityId()
val verifying: List<Saml2X509Credential> = registration.getAssertingPartyDetails().getVerificationX509Credentials()
        
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