Unfortunately, it's not possible to run or even install two Viewers of different versions on your machine. However, as an alternative you can run Portable Viewer of one of the versions instead - it does not require installation and stores all files in a single folder. For example, you can use installable Viewer of the latest version 22.214.171.124 and Portable Viewer of version 126.96.36.199 or vise versa. Both installable and portable Viewers are available for download on this page. Older versions of Remote Utilities, including Portable Viewer, are available here. However, please note that the version mismatch between Host and Viewer might also lead to performance issues or some features not working.