PuTTY Session Migration: Registry Schema Consistency Across Major Version Gaps

Session Configuration Persistence

PuTTY utilizes the Windows Registry under HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\Sessions to store session configurations. While configuration persistence is generally maintained across incremental updates, the behavior during migration between significantly different version releases remains undefined.

Configuration Boundary Uncertainty

Because PuTTY lacks a built-in rollback mechanism for registry-based settings, moving configurations from a legacy executable to a modern version introduces risks regarding schema changes. It is unclear if the application automatically maps legacy keys to new parameters or if deprecated settings are silently ignored during the loading process.

• Does PuTTY perform an automatic schema migration when detecting legacy session keys from older versions?
• What is the expected behavior when a modern version encounters a registry key that existed in a legacy version but is no longer supported?