---
title: Arez 0.48 released
author: Arez Project
authorURL: https://github.com/arez
---

[Full Changelog](https://github.com/arez/arez/compare/v0.47...v0.48)

Changes in this release:

#### Fixed
* **\[core\]** Fixed inefficiency where dependencies of an observer that are in a `POSSIBLY_STALE` state
  will cause the observer to be marked as `POSSIBLY_STALE` as the observers transaction is completing.
  This will schedule a potentially unnecessary reaction in the scenario where the dependency moves from
  `POSSIBLY_STALE` back to `UP_TO_DATE` as in when a `ComputedValue` is determined to not have changed.
  Now a dependency has to become `STALE` within a transaction before the observer will be rescheduled.

#### Changed
* **\[core\]** Enforced several constraints within code to catch unexpected scenarios such as; read-only
  observers triggering schedules of other observers, computed value observers triggering schedules of,
  self `reportPossiblyChanged` being invoked from read-only transactions etc. These scenarios should never
  occur but if they did would leave Arez in an inconsistent state. The invariants added catch these scenarios
  in development mode.
* **\[core\]** Added assertion to verify that transactions can no longer have dependent observables that do
  not have their `LeastStaleObserverState` kept up to date.

Update site to add news about the 0.48 release
Update site to add news about the 0.48 release
