Use the V5 ReleaseNotes page for any material going forward.
New Beans/Properties
idp.cookie.bufferingCondition
idp.encoding.forceUTF8
idp.logging.MDC.enabled
idp.logging.MDC.createSession
idp.authn.MFA.useLatestTimestamp
idp.authn.SAML.NameIDLookupStrategy
shibboleth.Conditions.EntityAttributes
shibboleth.Conditions.MappedEntityAttributes
shibboleth.TagCandidate
Programmer Visible (-api changes)
...