diff --git a/packages/web-api/src/types/request/files.ts b/packages/web-api/src/types/request/files.ts
index 8ad24f371..b4e7fa68e 100644
--- a/packages/web-api/src/types/request/files.ts
+++ b/packages/web-api/src/types/request/files.ts
@@ -128,7 +128,7 @@ export interface FileUploadBinaryContents {
 // File upload contents can be provided using either `content` or `file` arguments - and one of these is required.
 type FileUploadContents = FileUploadStringContents | FileUploadBinaryContents;
 
-type FileUpload = FileUploadContents & FileDestinationArgumentChannels & FileType & {
+type FileUpload = FileUploadContents & (FileDestinationArgumentChannels | FileDestinationArgument) & FileType & {
   /** @description Name of the file. */
   filename?: string;
   /** @description The message text introducing the file in specified channel(s). */
@@ -144,6 +144,8 @@ export type FileUploadV2 = FileUpload & {
   alt_text?: string;
   /** @description Channel ID where the file will be shared. If not specified the file will be private. */
   channel_id?: string;
+  /** @deprecated use channel_id instead */
+  channels?: string;
   /** @description Syntax type of the snippet being uploaded. E.g. `python`. */
   snippet_type?: string;
 };
diff --git a/packages/web-api/test/types/methods/files.test-d.ts b/packages/web-api/test/types/methods/files.test-d.ts
index 1e6675663..60e69d8ca 100644
--- a/packages/web-api/test/types/methods/files.test-d.ts
+++ b/packages/web-api/test/types/methods/files.test-d.ts
@@ -123,11 +123,20 @@ expectAssignable<Parameters<typeof web.files.uploadV2>>([{
   channels: 'C1234', // optionally share to one or more channels
   content: 'text',
 }]);
+expectAssignable<Parameters<typeof web.files.uploadV2>>([{
+  channel_id: 'C1234', // optionally share to one or more channels
+  content: 'text',
+}]);
 expectAssignable<Parameters<typeof web.files.uploadV2>>([{
   channels: 'C1234',
   thread_ts: '12345.67', // or even to a specific thread
   content: 'text',
 }]);
+expectAssignable<Parameters<typeof web.files.uploadV2>>([{
+  channel_id: 'C1234',
+  thread_ts: '12345.67', // or even to a specific thread
+  content: 'text',
+}]);
 
 // files.comments.delete
 // -- sad path