Several security researchers maintain archives of Sysmon executables for testing and legacy support.
https://download.sysinternals.com/files/sysmon.zip
Whether you are troubleshooting a legacy Windows Server 2008 R2 environment or need a specific version to match an existing configuration schema, finding official downloads for older versions of can be challenging. Microsoft typically only hosts the most recent version on its official download page . Where to Find Older Sysmon Versions
Snapshot from February 2021 (often contains v13.01 or similar). Sysmon 13.34: Available via a 2022 snapshot. 2. Community GitHub Repositories
Since there is no central official Microsoft repository for legacy versions, you must rely on community-maintained archives or web snapshots. 1. The Wayback Machine (Internet Archive)