The API already supports some extensions of <ref xmlns="http://www.tei-c.org/ns/1.0" target="https://github.com/TEI-Correspondence-SIG/CMIF/blob/main/proposals/CMIFv2_proposal.md">CMIF v2</ref>, such as the persons <hi xmlns="http://www.tei-c.org/ns/1.0" rendition="#i">mentioned</hi> and the URL to the corresponding TEI-XML full text. The latter makes it possible to find these letters in the full text search of correspSearch <ref xmlns="http://www.tei-c.org/ns/1.0" target="https://correspsearch.net/de/suche.html?q=fieber*">(example: “fieber*”)</ref>.