FLAGUPDATEOLD

FLAGUPDATEOLD is a symbolic constant used in software systems to signal that an update should be handled by the legacy or old update path. It commonly appears in configuration files, data migration scripts, or feature flag systems. When set to true (or 1), the system applies the legacy upgrade logic; when false (or 0), it uses the newer upgrade logic or default behavior. The flag is typically implemented as a boolean, but in some contexts may be represented as an integer or string value.

Rationale and use cases: FLAGUPDATEOLD supports backward compatibility during transitions between update schemes, allowing developers to maintain old behavior for certain records or clients while newer logic is introduced. It can facilitate staged rollouts, testing, and debugging of migration paths without affecting all users at once. The flag may be read at runtime by the update engine, migration script, or configuration loader.

Implementation notes: The flag can be stored in a database column, a JSON or YAML configuration, an environment variable, or compiled into code. Clear documentation of its semantics is essential to avoid mixed usage across components. Default values should be chosen carefully to prevent unintended behavior, and unit tests should cover both true and false branches.

Variants and naming: Common alternatives include UPDATE_OLD, USE_OLD_UPDATE_PATH, LEGACY_UPDATE_FLAG, and FLAG_USE_LEGACY. Consistent naming across a project improves readability and reduces misinterpretation.

See also: feature flag, backward compatibility, data migration, configuration management, upgrade path.