Exhibit 21.1

List of Subsidiaries of Upland Software, Inc. as of December 31, 2021

Upland Software Inc.

Upland Software UK Limited

Upland Software Australia Pty Ltd

Upland Software India Private Limited

Interfax Communications Limited

Return Fax 2000 Ltd.

Rapide Communications Ltd.

Rant & Rave Limited

Wire-E Limited

66099 Limited

Adestra Limited

Adestra Pty Limited

Altify Ireland Limited

Altify, Ltd.

Second Street Media, Inc.

myCapture, LLC

BlueVenn Group Limited

BlueVenn Group Holdings Limited

BlueDeveloper Limited

BlueVenn Holdings Limited

BlueVenn SA

BlueVenn Limited

Panviva Pty Ltd

Panviva Limited