# Release Selector

This command configures the tree in preparation for doing a staging release,
and pushes the result to try. The changes that that are made include:

- Updating the version number.
- Applying the migrations that are done as part of merge day.
- Disabling repacking most locales. (This can be disabled by passing `--no-limit-locales`).

For staging a beta release, run the following (with an appropriate version number):

```shell
mach try release --version 64.0b5 --migration main-to-beta
```

For staging a final release (rc or patch), run the following (with an appropriate version number)

```shell
mach try release --version 64.0 --migration main-to-beta --migration beta-to-release
```

Once the decision task is on the push is complete, you can start the release
through [staging ship-it instance](https://shipit.staging.mozilla-releng.net/new)[^shipit].

:::{note}
If pushing from beta or release, the corresponding migration should not be
passed, as they have already been applied.
:::

The `--tasks` flag controls the scope of the try push:

```{eval-rst}
.. option:: --tasks staging

   *(default)* Only shippable build-phase tasks (builds, signing, repackaging,
   PGO profiling) — the minimal set required before triggering a staging release
   via `ShipIt staging <https://shipit.staging.mozilla-releng.net/>`_.
```

```{eval-rst}
.. option:: --tasks release-sim

   Simulates a full release branch push, including tests. Used by sheriffs to
   look for branch-dependent test failures.
```

[^shipit]: This is only available to release engineering and release management (as of 2018-10-15).