fix(sync): read response headers case-insensitively

app/src/main/java/it/niedermann/owncloud/notes/persistence/CapabilitiesClient.java

@@ -22,6 +22,7 @@
 import it.niedermann.owncloud.notes.shared.model.Capabilities;
 import it.niedermann.owncloud.notes.shared.model.OcsResponse;
 import it.niedermann.owncloud.notes.shared.model.OcsUser;
+import it.niedermann.owncloud.notes.shared.util.extensions.HeaderExtensions;
 import retrofit2.Response;
 
 @WorkerThread
@@ -39,7 +40,7 @@ public static Capabilities getCapabilities(@NonNull Context context, @NonNull Si
             final var capabilities = response.getResponse().ocs.data;
             final var headers = response.getHeaders();
             if (headers != null) {
-                capabilities.setETag(headers.get(HEADER_KEY_ETAG));
+                capabilities.setETag(HeaderExtensions.getHeader(headers, HEADER_KEY_ETAG));
             } else {
                 Log.w(TAG, "Response headers of capabilities are null");
             }

app/src/main/java/it/niedermann/owncloud/notes/persistence/RemoteNotesMerger.kt

@@ -13,6 +13,7 @@ import it.niedermann.owncloud.notes.persistence.entity.Note
 import it.niedermann.owncloud.notes.shared.model.DBStatus
 import it.niedermann.owncloud.notes.shared.util.ApiVersionUtil
 import it.niedermann.owncloud.notes.shared.util.NoteUtil.generateNoteExcerpt
+import it.niedermann.owncloud.notes.shared.util.extensions.getHeader
 import java.util.Calendar
 import java.util.Date
 
@@ -82,15 +83,15 @@ class RemoteNotesMerger(private val repo: NotesRepository, private val localAcco
     }
 
     private fun updateSyncState(headers: Map<String, String>) {
-        localAccount.eTag = headers[HEADER_KEY_ETAG]
+        localAccount.eTag = headers.getHeader(HEADER_KEY_ETAG)
 
-        val lastModified = parseLastModified(headers[HEADER_KEY_LAST_MODIFIED])
+        val lastModified = parseLastModified(headers.getHeader(HEADER_KEY_LAST_MODIFIED))
         localAccount.modified = lastModified
 
         repo.updateETag(localAccount.id, localAccount.eTag)
         repo.updateModified(localAccount.id, lastModified.timeInMillis)
 
-        val newApiVersion = ApiVersionUtil.sanitize(headers[HEADER_KEY_X_NOTES_API_VERSIONS])
+        val newApiVersion = ApiVersionUtil.sanitize(headers.getHeader(HEADER_KEY_X_NOTES_API_VERSIONS))
         localAccount.apiVersion = newApiVersion
         repo.updateApiVersion(localAccount.id, newApiVersion)
         Log.d(TAG, "Pull: saved ETag ${localAccount.eTag}, last modified ${lastModified.time}, API $newApiVersion")

app/src/main/java/it/niedermann/owncloud/notes/shared/util/extensions/HeaderExtensions.kt

@@ -0,0 +1,12 @@
+/*
+ * Nextcloud - Android Client
+ *
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+@file:JvmName("HeaderExtensions")
+
+package it.niedermann.owncloud.notes.shared.util.extensions
+
+fun Map<String, String>.getHeader(name: String): String? =
+    entries.firstOrNull { it.key.equals(name, ignoreCase = true) }?.value

app/src/test/java/it/niedermann/owncloud/notes/shared/util/extensions/HeaderExtensionsTest.kt

@@ -0,0 +1,31 @@
+/*
+ * Nextcloud - Android Client
+ *
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+package it.niedermann.owncloud.notes.shared.util.extensions
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNull
+import org.junit.Test
+
+class HeaderExtensionsTest {
+
+    @Test
+    fun getHeaderMatchesExactCase() {
+        assertEquals("\"abc\"", mapOf("ETag" to "\"abc\"").getHeader("ETag"))
+    }
+
+    @Test
+    fun getHeaderMatchesLowercaseNameFromProxy() {
+        val headers = mapOf("etag" to "\"abc\"", "last-modified" to "Mon, 30 Dec 2024 20:52:52 GMT")
+        assertEquals("\"abc\"", headers.getHeader("ETag"))
+        assertEquals("Mon, 30 Dec 2024 20:52:52 GMT", headers.getHeader("Last-Modified"))
+    }
+
+    @Test
+    fun getHeaderReturnsNullWhenMissing() {
+        assertNull(mapOf("Server" to "Apache").getHeader("ETag"))
+    }
+}