This brings forward the 2.3 merged part of pull 2336 (#2404)

monkeyiq · monkeyiq · commit 8f0001365410 · 2025-03-17T16:15:46.000+10:00
#2336 (comment)
diff --git a/modules/saml/src/Auth/Source/SP.php b/modules/saml/src/Auth/Source/SP.php
@@ -596,6 +596,8 @@ private function startSSO2(Configuration $idpMetadata, array $state): Response
             $idpEntry = [];
             if (isset($state['IDPList'])) {
                 $idpList = $state['IDPList'];
+            } elseif (isset($state['saml:IDPList'])) {
+                $idpList = $state['saml:IDPList'];
             } elseif (!empty($this->metadata->getOptionalArray('IDPList', []))) {
                 foreach ($this->metadata->getArray('IDPList') as $entry) {
                     $idpEntry[] = new IDPEntry($entry);
