While the Official AnyDesk Website provides an archive for legacy releases, many users turn to reputable third-party repositories for specific older builds like 5.5.3:
Designed for high frame rates and minimal lag, even on lower bandwidth. AnyDesk 5.5.3 Free Download
Useful for IT professionals who need the MSI installer for automated deployments. AnyDesk Remote Desktop - Apps on Google Play While the Official AnyDesk Website provides an archive