diff --git a/docs/API.md b/docs/API.md
index 5366f0f..6e7cf2a 100644
--- a/docs/API.md
+++ b/docs/API.md
@@ -155,7 +155,7 @@ ArchiveRecord {
 ```
 CreateArchiveRecordParams {
   s3Url: string;
-  file: Pick<File, 'contentType' | 'size'>;
+  file: Pick<Partial<File>, 'contentType'> & Pick<File, 'size'>;
   item: Pick<ArchiveRecord, 'displayName' | 'fileSystemCompatibleName'>;
   parentFolder: Pick<Folder, 'id'>;
 }
@@ -165,6 +165,9 @@ s3Url will generally be the value returned by `uploadFile`. Run
 `createArchiveRecord` to store information about uploaded files in the
 Permanent database.
 
+file.contentType is deprecated. The field is still accepted for backwards compatibility, but it is not used.
+The content type is determined by the file extension of the uploaded file.
+
 ```
 createArchiveRecord(
   clientConfiguration: ClientConfiguration,
diff --git a/src/api/createRecordVo.ts b/src/api/createRecordVo.ts
index 9b0358e..edabfb6 100644
--- a/src/api/createRecordVo.ts
+++ b/src/api/createRecordVo.ts
@@ -13,7 +13,7 @@ export interface CreateRecordVoRequest {
   displayName: string;
   parentFolderId: number;
   uploadFileName: string;
-  fileType: string;
+  fileType?: string;
   size: number;
 }
 
diff --git a/src/sdk/createArchiveRecord.ts b/src/sdk/createArchiveRecord.ts
index dd93c80..9c2380a 100644
--- a/src/sdk/createArchiveRecord.ts
+++ b/src/sdk/createArchiveRecord.ts
@@ -13,7 +13,7 @@ import type {
 
 export interface CreateArchiveRecordParams {
   s3Url: string;
-  file: Pick<File, 'contentType' | 'size'>;
+  file: Pick<Partial<File>, 'contentType'> & Pick<File, 'size'>;
   item: Pick<ArchiveRecord, 'displayName' | 'fileSystemCompatibleName'>;
   parentFolder: Pick<Folder, 'id'>;
 }