The Shibboleth IdP V4 software will leave support on September 1, 2024.

ExternalAttributePluginActivationConditions

Attribute Encoders, Attribute Definitions and Data Connectors can be supplemented with an externally-defined activation condition. This is done via the attribute activationConditionRef. 

The most common condition (by relying party ID) can be done using the relyingParties attribute