{"version":"2.1.228","anchor":"some-request-headers-now-append-instead-of-replace","canonical_anchor":"some-request-headers-now-append-instead-of-replace","heading":"Some request headers now append instead of replace","tier":"internal","area":"API Client","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.228\/e\/some-request-headers-now-append-instead-of-replace","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.228","markdown":"### Some request headers now append instead of replace\n\nA few request headers now combine values instead of the last one overwriting the rest.\n\n**What**\n\nThe SDK's header merging gained a small set of names, currently `x-stainless-helper`, that combine by comma-joining unique trimmed values instead of the later value winning, plus a sentinel that clears a header and stops later values appending to it.\n\n**Evidence**\n\n`x-stainless-helper`\n\n- Area: API Client\n- Tier: Under the hood\n- Useful: 1\/5\n- Signal: 1\/5"}