# Problem code `'deprecated'`

> Contract 2.0.0 · package sha256 `a857eca95b35921109faf997094bb4192f12527d9d0fcd4be7e97f06425bad6e` · generated from `configurator-runtime.d.ts`, `tables/problems.json` and `services/onsite-scripter/scripts/contract-docs-what-to-do.json` by `services/onsite-scripter/scripts/build-contract-docs.mjs`; edit the source, not this file.

A member of [`ProblemCode`](../api/ProblemCode.md) · stable · since 2.0.0

Reserved for a labs member or value that will change; the strict fake throws on it. No 2.0.0 member is deprecated, so no 2.0.0 call records it.

## What to do

A labs member or value you use will change in a later minor: read the Problem's `message` and move off it, and run your tests on a strict fake ([`testing.FakeSessionOptions.strict`](../api/testing.FakeSessionOptions.strict.md)), which throws on it.

## Where the declaration names it

- [`testing.FakeSessionOptions.strict`](../api/testing.FakeSessionOptions.strict.md): Throws the runtime's errors and records every Problem, plus fake-only checks: a wrong-writer write after an `await` (tracked with AsyncLocalStorage) throws HoloScopeError; a `session` read of a target with a write queued behind an open transaction records 'read-while-queued', inside `work` too, while a read through that transaction's `tx` records nothing (read through `tx` inside `work`); a call…

The set is open: handle a code you don't know (`'other'`).