v2.1.0

Release note

• #102 Add support for relay state in SAML request (@puneetmakkar)
• #100 Key matching scheme for signing certificates
• #99 Updating checkSignature spellings (@puneetmakkar)

This release includes a new important feature (#100). Multiple signing certificates in metadata is allowed in SAML2 specification, some IdP might choose to roll the usage of different keys, therefore, service provider should be able to check if the one specified in SAML response is already specified in the metadata, it's just like a whitelist checking and an error will be thrown if there is no matching key. Last but not least, thanks for @puneetmakkar your two pull requests as well.