curver

CurVer is a registry mechanism used by the Windows operating system to indicate the current version of a programmatic identifier (ProgID) in the Component Object Model (COM) infrastructure. It is stored as a string value named CurVer under a ProgID key in the Windows Registry, typically under HKEY_CLASSES_ROOT.

The CurVer value points from an unversioned ProgID to a versioned ProgID. For example, a key such as HKEY_CLASSES_ROOT\Word.Application may contain a CurVer value that references Word.Application.16, meaning that the unversioned ProgID Word.Application should resolve to the versioned ProgID Word.Application.16. This enables client code that uses the stable, unversioned ProgID to continue working when newer versions of the component are installed, by redirecting to the current version’s ProgID automatically.

Use and implications: CurVer helps preserve backward compatibility in scripted and programmatic automation scenarios. It also provides a single site of management for versioning behavior. However, reliance on CurVer can hide version-specific behavior, and changes to CurVer mappings can cause automation to bind to a different version than expected. If the target versioned ProgID is removed or altered, automation that depends on CurVer may fail.

Viewing and modifying CurVer is done through the Windows Registry (Regedit) by users with appropriate privileges. Caution is advised, as incorrect edits can destabilize COM registrations. Related concepts include ProgID, CLSID, COM, Windows Registry, and ActiveX. CurVer remains a common, though optional, mechanism for version management within the Windows COM ecosystem.