upgrade.md

# Upgrading Synapse

Before upgrading check if any special steps are required to upgrade from
the version you currently have installed to the current version of
Synapse. The extra instructions that may be required are listed later in
this document.

-   Check that your versions of Python and PostgreSQL are still
    supported.

    Synapse follows upstream lifecycles for [Python](https://endoflife.date/python) and
    [PostgreSQL](https://endoflife.date/postgresql), and removes support for versions
    which are no longer maintained.

    The website <https://endoflife.date> also offers convenient
    summaries.

-   If Synapse was installed using [prebuilt
    packages](setup/installation.md#prebuilt-packages), you will need to follow the
    normal process for upgrading those packages.

-   If Synapse was installed using pip then upgrade to the latest
    version by running:

    ```bash
    pip install --upgrade matrix-synapse
    ```

-   If Synapse was installed from source, then:

    1.  Obtain the latest version of the source code. Git users can run
        `git pull` to do this.

    2.  If you're running Synapse in a virtualenv, make sure to activate it before
        upgrading. For example, if Synapse is installed in a virtualenv in `~/synapse/env` then
        run:

        ```bash
        source ~/synapse/env/bin/activate
        pip install --upgrade .
        ```
        Include any relevant extras between square brackets, e.g. `pip install --upgrade ".[postgres,oidc]"`.

    3.  If you're using `poetry` to manage a Synapse installation, run:
        ```bash
        poetry install
        ```
        Include any relevant extras with `--extras`, e.g. `poetry install --extras postgres --extras oidc`.
        It's probably easiest to run `poetry install --extras all`.

    4.  Restart Synapse:

        ```bash
        synctl restart
        ```

To check whether your update was successful, you can check the running
server version with:

```bash
# you may need to replace 'localhost:8008' if synapse is not configured
# to listen on port 8008.

curl http://localhost:8008/_synapse/admin/v1/server_version
```

## Rolling back to older versions

Rolling back to previous releases can be difficult, due to database
schema changes between releases. Where we have been able to test the
rollback process, this will be noted below.

In general, you will need to undo any changes made during the upgrade
process, for example:

-   pip:

    ```bash
    source env/bin/activate
    # replace `1.3.0` accordingly:
    pip install matrix-synapse==1.3.0
    ```

-   Debian:

    ```bash
    # replace `1.3.0` and `stretch` accordingly:
    wget https://packages.matrix.org/debian/pool/main/m/matrix-synapse-py3/matrix-synapse-py3_1.3.0+stretch1_amd64.deb
    dpkg -i matrix-synapse-py3_1.3.0+stretch1_amd64.deb
    ```

# Upgrading to v1.67.0

## Direct TCP replication is no longer supported: migrate to Redis

Redis support was added in v1.13.0 with it becoming the recommended method in
v1.18.0. It replaced the old direct TCP connections (which was deprecated as of
v1.18.0) to the main process. With Redis, rather than all the workers connecting
to the main process, all the workers and the main process connect to Redis,
which relays replication commands between processes. This can give a significant
CPU saving on the main process and is a prerequisite for upcoming
performance improvements.

To migrate to Redis add the [`redis` config](./workers.md#shared-configuration),
and remove the TCP `replication` listener from config of the master and
`worker_replication_port` from worker config. Note that a HTTP listener with a
`replication` resource is still required.

## Minimum version of Poetry is now v1.2.0

The minimum supported version of poetry is now 1.2. This should only affect
those installing from a source checkout.

## Rust requirement in the next release

From the next major release (v1.68.0) installing Synapse from a source checkout
will require a recent Rust compiler. Those using packages or
`pip install matrix-synapse` will not be affected.

The simplest way of installing Rust is via [rustup.rs](https://rustup.rs/)

## SQLite version requirement in the next release

From the next major release (v1.68.0) Synapse will require SQLite 3.27.0 or 
higher. Synapse v1.67.0 will be the last major release supporting SQLite
versions 3.22 to 3.26.

Those using docker images or Debian packages from Matrix.org will not be
affected. If you have installed from source, you should check the version of 
SQLite used by Python with:

```shell
python -c "import sqlite3; print(sqlite3.sqlite_version)"
```

If this is too old, refer to your distribution for advice on upgrading.

# Upgrading to v1.66.0

## Delegation of email validation no longer supported

As of this version, Synapse no longer allows the tasks of verifying email address
ownership, and password reset confirmation, to be delegated to an identity server.
This removal was previously planned for Synapse 1.64.0, but was
[delayed](https://github.com/matrix-org/synapse/issues/13421) until now to give
homeserver administrators more notice of the change.

To continue to allow users to add email addresses to their homeserver accounts,
and perform password resets, make sure that Synapse is configured with a working
email server in the [`email` configuration
section](https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#email)
(including, at a minimum, a `notif_from` setting.)

Specifying an `email` setting under `account_threepid_delegates` will now cause
an error at startup.

# Upgrading to v1.64.0

## Deprecation of the ability to delegate e-mail verification to identity servers

Synapse v1.66.0 will remove the ability to delegate the tasks of verifying email address ownership, and password reset confirmation, to an identity server.

If you require your homeserver to verify e-mail addresses or to support password resets via e-mail, please configure your homeserver with SMTP access so that it can send e-mails on its own behalf.
[Consult the configuration documentation for more information.](https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#email)

The option that will be removed is `account_threepid_delegates.email`.


## Changes to the event replication streams

Synapse now includes a flag indicating if an event is an outlier when
replicating it to other workers. This is a forwards- and backwards-incompatible
change: v1.63 and workers cannot process events replicated by v1.64 workers, and
vice versa.

Once all workers are upgraded to v1.64 (or downgraded to v1.63), event
replication will resume as normal.

## frozendict release

[frozendict 2.3.3](https://github.com/Marco-Sulla/python-frozendict/releases/tag/v2.3.3)
has recently been released, which fixes a memory leak that occurs during `/sync`
requests. We advise server administrators who installed Synapse via pip to upgrade
frozendict with `pip install --upgrade frozendict`. The Docker image
`matrixdotorg/synapse` and the Debian packages from `packages.matrix.org` already
include the updated library.

# Upgrading to v1.62.0

## New signatures for spam checker callbacks

As a followup to changes in v1.60.0, the following spam-checker callbacks have changed signature:

- `user_may_join_room`
- `user_may_invite`
- `user_may_send_3pid_invite`
- `user_may_create_room`
- `user_may_create_room_alias`
- `user_may_publish_room`
- `check_media_file_for_spam`

For each of these methods, the previous callback signature has been deprecated.

Whereas callbacks used to return `bool`, they should now return `Union["synapse.module_api.NOT_SPAM", "synapse.module_api.errors.Codes"]`.

For instance, if your module implements `user_may_join_room` as follows:

```python
async def user_may_join_room(self, user_id: str, room_id: str, is_invited: bool)
    if ...:
        # Request is spam
        return False
    # Request is not spam
    return True
```

you should rewrite it as follows:

```python
async def user_may_join_room(self, user_id: str, room_id: str, is_invited: bool)
    if ...:
        # Request is spam, mark it as forbidden (you may use some more precise error
        # code if it is useful).
        return synapse.module_api.errors.Codes.FORBIDDEN
    # Request is not spam, mark it as such.
    return synapse.module_api.NOT_SPAM
```

# Upgrading to v1.61.0

## Removal of deprecated community/groups

This release of Synapse will remove deprecated community/groups from codebase.

### Worker endpoints

For those who have deployed workers, following worker endpoints will no longer
exist and they can be removed from the reverse proxy configuration:

-   `^/_matrix/federation/v1/get_groups_publicised$`
-   `^/_matrix/client/(r0|v3|unstable)/joined_groups$`
-   `^/_matrix/client/(r0|v3|unstable)/publicised_groups$`
-   `^/_matrix/client/(r0|v3|unstable)/publicised_groups/`
-   `^/_matrix/federation/v1/groups/`
-   `^/_matrix/client/(r0|v3|unstable)/groups/`

# Upgrading to v1.60.0

## Adding a new unique index to `state_group_edges` could fail if your database is corrupted

This release of Synapse will add a unique index to the `state_group_edges` table, in order
to prevent accidentally introducing duplicate information (for example, because a database
backup was restored multiple times).

Duplicate rows being present in this table could cause drastic performance problems; see
[issue 11779](https://github.com/matrix-org/synapse/issues/11779) for more details.

If your Synapse database already has had duplicate rows introduced into this table,
this could fail, with either of these errors:


**On Postgres:**
```
synapse.storage.background_updates - 623 - INFO - background_updates-0 - Adding index state_group_edges_unique_idx to state_group_edges
synapse.storage.background_updates - 282 - ERROR - background_updates-0 - Error doing update
...
psycopg2.errors.UniqueViolation: could not create unique index "state_group_edges_unique_idx"
DETAIL:  Key (state_group, prev_state_group)=(2, 1) is duplicated.
```
(The numbers may be different.)

**On SQLite:**
```
synapse.storage.background_updates - 623 - INFO - background_updates-0 - Adding index state_group_edges_unique_idx to state_group_edges
synapse.storage.background_updates - 282 - ERROR - background_updates-0 - Error doing update
...
sqlite3.IntegrityError: UNIQUE constraint failed: state_group_edges.state_group, state_group_edges.prev_state_group
```


<details>
<summary><b>Expand this section for steps to resolve this problem</b></summary>

### On Postgres

Connect to your database with `psql`.

```sql
BEGIN;
DELETE FROM state_group_edges WHERE (ctid, state_group, prev_state_group) IN (
  SELECT row_id, state_group, prev_state_group
  FROM (
    SELECT
      ctid AS row_id,
      MIN(ctid) OVER (PARTITION BY state_group, prev_state_group) AS min_row_id,
      state_group,
      prev_state_group
    FROM state_group_edges
  ) AS t1
  WHERE row_id <> min_row_id
);
COMMIT;
```


### On SQLite

At the command-line, use `sqlite3 path/to/your-homeserver-database.db`:

```sql
BEGIN;
DELETE FROM state_group_edges WHERE (rowid, state_group, prev_state_group) IN (
  SELECT row_id, state_group, prev_state_group
  FROM (
    SELECT
      rowid AS row_id,
      MIN(rowid) OVER (PARTITION BY state_group, prev_state_group) AS min_row_id,
      state_group,
      prev_state_group
    FROM state_group_edges
  )
  WHERE row_id <> min_row_id
);
COMMIT;
```


### For more details

[This comment on issue 11779](https://github.com/matrix-org/synapse/issues/11779#issuecomment-1131545970)
has queries that can be used to check a database for this problem in advance.

</details>

## New signature for the spam checker callback `check_event_for_spam`

The previous signature has been deprecated.

Whereas `check_event_for_spam` callbacks used to return `Union[str, bool]`, they should now return `Union["synapse.module_api.NOT_SPAM", "synapse.module_api.errors.Codes"]`.

This is part of an ongoing refactoring of the SpamChecker API to make it less ambiguous and more powerful.

If your module implements `check_event_for_spam` as follows:

```python
async def check_event_for_spam(event):
    if ...:
        # Event is spam
        return True
    # Event is not spam
    return False
```

you should rewrite it as follows:

```python
async def check_event_for_spam(event):
    if ...:
        # Event is spam, mark it as forbidden (you may use some more precise error
        # code if it is useful).
        return synapse.module_api.errors.Codes.FORBIDDEN
    # Event is not spam, mark it as such.
    return synapse.module_api.NOT_SPAM
```

# Upgrading to v1.59.0

## Device name lookup over federation has been disabled by default

The names of user devices are no longer visible to users on other homeservers by default.
Device IDs are unaffected, as these are necessary to facilitate end-to-end encryption.

To re-enable this functionality, set the
[`allow_device_name_lookup_over_federation`](https://matrix-org.github.io/synapse/v1.59/usage/configuration/config_documentation.html#federation)
homeserver config option to `true`.


## Deprecation of the `synapse.app.appservice` and `synapse.app.user_dir` worker application types

The `synapse.app.appservice` worker application type allowed you to configure a
single worker to use to notify application services of new events, as long
as this functionality was disabled on the main process with `notify_appservices: False`.
Further, the `synapse.app.user_dir` worker application type allowed you to configure
a single worker to be responsible for updating the user directory, as long as this
was disabled on the main process with `update_user_directory: False`.

To unify Synapse's worker types, the `synapse.app.appservice` worker application
type and the `notify_appservices` configuration option have been deprecated.
The `synapse.app.user_dir` worker application type and `update_user_directory`
configuration option have also been deprecated.

To get the same functionality as was provided by the deprecated options, it's now recommended that the `synapse.app.generic_worker`
worker application type is used and that the `notify_appservices_from_worker` and/or
`update_user_directory_from_worker` options are set to the name of a worker.

For the time being, the old options can be used alongside the new options to make
it easier to transition between the two configurations, however please note that:

- the options must not contradict each other (otherwise Synapse won't start); and
- the `notify_appservices` and `update_user_directory` options will be removed in a future release of Synapse.

Please see the [*Notifying Application Services*][v1_59_notify_ases_from] and
[*Updating the User Directory*][v1_59_update_user_dir] sections of the worker
documentation for more information.

[v1_59_notify_ases_from]: workers.md#notifying-application-services
[v1_59_update_user_dir]: workers.md#updating-the-user-directory


# Upgrading to v1.58.0

## Groups/communities feature has been disabled by default

The non-standard groups/communities feature in Synapse has been disabled by default
and will be removed in Synapse v1.61.0.


# Upgrading to v1.57.0

## Changes to database schema for application services

Synapse v1.57.0 includes a [change](https://github.com/matrix-org/synapse/pull/12209) to the
way transaction IDs are managed for application services. If your deployment uses a dedicated
worker for application service traffic, **it must be stopped** when the database is upgraded
(which normally happens when the main process is upgraded), to ensure the change is made safely
without any risk of reusing transaction IDs.

Deployments which do not use separate worker processes can be upgraded as normal. Similarly,
deployments where no application services are in use can be upgraded as normal.

<details>
<summary><b>Recovering from an incorrect upgrade</b></summary>

If the database schema is upgraded *without* stopping the worker responsible
for AS traffic, then the following error may be given when attempting to start
a Synapse worker or master process:

```
**********************************************************************************
 Error during initialisation:

 Postgres sequence 'application_services_txn_id_seq' is inconsistent with associated
 table 'application_services_txns'. This can happen if Synapse has been downgraded and
 then upgraded again, or due to a bad migration.

 To fix this error, shut down Synapse (including any and all workers)
 and run the following SQL:

     SELECT setval('application_services_txn_id_seq', (
         SELECT GREATEST(MAX(txn_id), 0) FROM application_services_txns
     ));

 See docs/postgres.md for more information.

 There may be more information in the logs.
**********************************************************************************
```

This error may also be seen if Synapse is *downgraded* to an earlier version,
and then upgraded again to v1.57.0 or later.

In either case:

 1. Ensure that the worker responsible for AS traffic is stopped.
 2. Run the SQL command given in the error message via `psql`.

Synapse should then start correctly.
</details>

# Upgrading to v1.56.0

## Open registration without verification is now disabled by default

Synapse will refuse to start if registration is enabled without email, captcha, or token-based verification unless the new config
flag `enable_registration_without_verification` is set to "true".

## Groups/communities feature has been deprecated

The non-standard groups/communities feature in Synapse has been deprecated and will
be disabled by default in Synapse v1.58.0.

You can test disabling it by adding the following to your homeserver configuration:

```yaml
experimental_features:
  groups_enabled: false
```

## Change in behaviour for PostgreSQL databases with unsafe locale

Synapse now refuses to start when using PostgreSQL with non-`C` values for `COLLATE` and
`CTYPE` unless the config flag `allow_unsafe_locale`, found in the database section of
the configuration file, is set to `true`. See the [PostgreSQL documentation](https://matrix-org.github.io/synapse/latest/postgres.html#fixing-incorrect-collate-or-ctype)
for more information and instructions on how to fix a database with incorrect values.

# Upgrading to v1.55.0

## `synctl` script has been moved

The `synctl` script
[has been made](https://github.com/matrix-org/synapse/pull/12140) an
[entry point](https://packaging.python.org/en/latest/specifications/entry-points/)
and no longer exists at the root of Synapse's source tree. If you wish to use
`synctl` to manage your homeserver, you should invoke `synctl` directly, e.g.
`synctl start` instead of `./synctl start` or `/path/to/synctl start`.

You will need to ensure `synctl` is on your `PATH`.
  - This is automatically the case when using
    [Debian packages](https://packages.matrix.org/debian/) or
    [docker images](https://hub.docker.com/r/matrixdotorg/synapse)
    provided by Matrix.org.
  - When installing from a wheel, sdist, or PyPI, a `synctl` executable is added
    to your Python installation's `bin`. This should be on your `PATH`
    automatically, though you might need to activate a virtual environment
    depending on how you installed Synapse.


## Compatibility dropped for Mjolnir 1.3.1 and earlier

Synapse v1.55.0 drops support for Mjolnir 1.3.1 and earlier.
If you use the Mjolnir module to moderate your homeserver,
please upgrade Mjolnir to version 1.3.2 or later before upgrading Synapse.


# Upgrading to v1.54.0

## Legacy structured logging configuration removal

This release removes support for the `structured: true` logging configuration
which was deprecated in Synapse v1.23.0. If your logging configuration contains
`structured: true` then it should be modified based on the
[structured logging documentation](https://matrix-org.github.io/synapse/v1.56/structured_logging.html#upgrading-from-legacy-structured-logging-configuration).

# Upgrading to v1.53.0

## Dropping support for `webclient` listeners and non-HTTP(S) `web_client_location`

Per the deprecation notice in Synapse v1.51.0, listeners of type  `webclient`
are no longer supported and configuring them is a now a configuration error.

Configuring a non-HTTP(S) `web_client_location` configuration is is now a
configuration error. Since the `webclient` listener is no longer supported, this
setting only applies to the root path `/` of Synapse's web server and no longer
the `/_matrix/client/` path.

## Stablisation of MSC3231

The unstable validity-check endpoint for the
[Registration Tokens](https://spec.matrix.org/v1.2/client-server-api/#get_matrixclientv1registermloginregistration_tokenvalidity)
feature has been stabilised and moved from:

`/_matrix/client/unstable/org.matrix.msc3231/register/org.matrix.msc3231.login.registration_token/validity`

to:

`/_matrix/client/v1/register/m.login.registration_token/validity`

Please update any relevant reverse proxy or firewall configurations appropriately.

## Time-based cache expiry is now enabled by default

Formerly, entries in the cache were not evicted regardless of whether they were accessed after storing.
This behavior has now changed. By default entries in the cache are now evicted after 30m of not being accessed.
To change the default behavior, go to the `caches` section of the config and change the `expire_caches` and
`cache_entry_ttl` flags as necessary. Please note that these flags replace the `expiry_time` flag in the config.
The `expiry_time` flag will still continue to work, but it has been deprecated and will be removed in the future.

## Deprecation of `capability` `org.matrix.msc3283.*`

The `capabilities` of MSC3283 from the REST API `/_matrix/client/r0/capabilities`
becomes stable.

The old `capabilities`
- `org.matrix.msc3283.set_displayname`,
- `org.matrix.msc3283.set_avatar_url` and
- `org.matrix.msc3283.3pid_changes`

are deprecated and scheduled to be removed in Synapse v1.54.0.

The new `capabilities`
- `m.set_displayname`,
- `m.set_avatar_url` and
- `m.3pid_changes`

are now active by default.

## Removal of `user_may_create_room_with_invites`

As announced with the release of [Synapse 1.47.0](#deprecation-of-the-user_may_create_room_with_invites-module-callback),
the deprecated `user_may_create_room_with_invites` module callback has been removed.

Modules relying on it can instead implement [`user_may_invite`](https://matrix-org.github.io/synapse/latest/modules/spam_checker_callbacks.html#user_may_invite)
and use the [`get_room_state`](https://github.com/matrix-org/synapse/blob/872f23b95fa980a61b0866c1475e84491991fa20/synapse/module_api/__init__.py#L869-L876)
module API to infer whether the invite is happening while creating a room (see [this function](https://github.com/matrix-org/synapse-domain-rule-checker/blob/e7d092dd9f2a7f844928771dbfd9fd24c2332e48/synapse_domain_rule_checker/__init__.py#L56-L89)
as an example). Alternately, modules can also implement [`on_create_room`](https://matrix-org.github.io/synapse/latest/modules/third_party_rules_callbacks.html#on_create_room).


# Upgrading to v1.52.0

## Twisted security release

Note that [Twisted 22.1.0](https://github.com/twisted/twisted/releases/tag/twisted-22.1.0)
has recently been released, which fixes a [security issue](https://github.com/twisted/twisted/security/advisories/GHSA-92x2-jw7w-xvvx)
within the Twisted library. We do not believe Synapse is affected by this vulnerability,
though we advise server administrators who installed Synapse via pip to upgrade Twisted
with `pip install --upgrade Twisted treq` as a matter of good practice. The Docker image
`matrixdotorg/synapse` and the Debian packages from `packages.matrix.org` are using the
updated library.

# Upgrading to v1.51.0

## Deprecation of `webclient` listeners and non-HTTP(S) `web_client_location`

Listeners of type  `webclient` are deprecated and scheduled to be removed in
Synapse v1.53.0.

Similarly, a non-HTTP(S) `web_client_location` configuration is deprecated and
will become a configuration error in Synapse v1.53.0.


# Upgrading to v1.50.0

## Dropping support for old Python and Postgres versions

In line with our [deprecation policy](deprecation_policy.md),
we've dropped support for Python 3.6 and PostgreSQL 9.6, as they are no
longer supported upstream.

This release of Synapse requires Python 3.7+ and PostgreSQL 10+.


# Upgrading to v1.47.0

## Removal of old Room Admin API

The following admin APIs were deprecated in [Synapse 1.34](https://github.com/matrix-org/synapse/blob/v1.34.0/CHANGES.md#deprecations-and-removals)
(released on 2021-05-17) and have now been removed:

- `POST /_synapse/admin/v1/<room_id>/delete`

Any scripts still using the above APIs should be converted to use the
[Delete Room API](https://matrix-org.github.io/synapse/latest/admin_api/rooms.html#delete-room-api).

## Deprecation of the `user_may_create_room_with_invites` module callback

The `user_may_create_room_with_invites` is deprecated and will be removed in a future
version of Synapse. Modules implementing this callback can instead implement
[`user_may_invite`](https://matrix-org.github.io/synapse/latest/modules/spam_checker_callbacks.html#user_may_invite)
and use the [`get_room_state`](https://github.com/matrix-org/synapse/blob/872f23b95fa980a61b0866c1475e84491991fa20/synapse/module_api/__init__.py#L869-L876)
module API method to infer whether the invite is happening in the context of creating a
room.

We plan to remove this callback in January 2022.

# Upgrading to v1.45.0

## Changes required to media storage provider modules when reading from the Synapse configuration object

Media storage provider modules that read from the Synapse configuration object (i.e. that
read the value of `hs.config.[...]`) now need to specify the configuration section they're
reading from. This means that if a module reads the value of e.g. `hs.config.media_store_path`,
it needs to replace it with `hs.config.media.media_store_path`.

# Upgrading to v1.44.0

## The URL preview cache is no longer mirrored to storage providers
The `url_cache/` and `url_cache_thumbnails/` directories in the media store are
no longer mirrored to storage providers. These two directories can be safely
deleted from any configured storage providers to reclaim space.

# Upgrading to v1.43.0

## The spaces summary APIs can now be handled by workers

The [available worker applications documentation](https://matrix-org.github.io/synapse/latest/workers.html#available-worker-applications)
has been updated to reflect that calls to the `/spaces`, `/hierarchy`, and
`/summary` endpoints can now be routed to workers for both client API and
federation requests.

# Upgrading to v1.42.0

## Removal of old Room Admin API

The following admin APIs were deprecated in [Synapse 1.25](https://github.com/matrix-org/synapse/blob/v1.25.0/CHANGES.md#removal-warning)
(released on 2021-01-13) and have now been removed:

-   `POST /_synapse/admin/v1/purge_room`
-   `POST /_synapse/admin/v1/shutdown_room/<room_id>`

Any scripts still using the above APIs should be converted to use the
[Delete Room API](https://matrix-org.github.io/synapse/latest/admin_api/rooms.html#delete-room-api).

## User-interactive authentication fallback templates can now display errors

This may affect you if you make use of custom HTML templates for the
[reCAPTCHA](../synapse/res/templates/recaptcha.html) or
[terms](../synapse/res/templates/terms.html) fallback pages.

The template is now provided an `error` variable if the authentication
process failed. See the default templates linked above for an example.

## Removal of out-of-date email pushers

Users will stop receiving message updates via email for addresses that were
once, but not still, linked to their account.

# Upgrading to v1.41.0

## Add support for routing outbound HTTP requests via a proxy for federation

Since Synapse 1.6.0 (2019-11-26) you can set a proxy for outbound HTTP requests via
http_proxy/https_proxy environment variables. This proxy was set for:
- push
- url previews
- phone-home stats
- recaptcha validation
- CAS auth validation
- OpenID Connect
- Federation (checking public key revocation)

In this version we have added support for outbound requests for:
- Outbound federation
- Downloading remote media
- Fetching public keys of other servers

These requests use the same proxy configuration. If you have a proxy configuration we
recommend to verify the configuration. It may be necessary to adjust the `no_proxy`
environment variable.

See [using a forward proxy with Synapse documentation](setup/forward_proxy.md) for
details.

## Deprecation of `template_dir`

The `template_dir` settings in the `sso`, `account_validity` and `email` sections of the
configuration file are now deprecated. Server admins should use the new
`templates.custom_template_directory` setting in the configuration file and use one single
custom template directory for all aforementioned features. Template file names remain
unchanged. See [the related documentation](https://matrix-org.github.io/synapse/latest/templates.html)
for more information and examples.

We plan to remove support for these settings in October 2021.

## `/_synapse/admin/v1/users/{userId}/media` must be handled by media workers

The [media repository worker documentation](https://matrix-org.github.io/synapse/latest/workers.html#synapseappmedia_repository)
has been updated to reflect that calls to `/_synapse/admin/v1/users/{userId}/media`
must now be handled by media repository workers. This is due to the new `DELETE` method
of this endpoint modifying the media store.

# Upgrading to v1.39.0

## Deprecation of the current third-party rules module interface

The current third-party rules module interface is deprecated in favour of the new generic
modules system introduced in Synapse v1.37.0. Authors of third-party rules modules can refer
to [this documentation](modules/porting_legacy_module.md)
to update their modules. Synapse administrators can refer to [this documentation](modules/index.md)
to update their configuration once the modules they are using have been updated.

We plan to remove support for the current third-party rules interface in September 2021.


# Upgrading to v1.38.0

## Re-indexing of `events` table on Postgres databases

This release includes a database schema update which requires re-indexing one of
the larger tables in the database, `events`. This could result in increased
disk I/O for several hours or days after upgrading while the migration
completes. Furthermore, because we have to keep the old indexes until the new
indexes are ready, it could result in a significant, temporary, increase in
disk space.

To get a rough idea of the disk space required, check the current size of one
of the indexes. For example, from a `psql` shell, run the following sql:

```sql
SELECT pg_size_pretty(pg_relation_size('events_order_room'));
```

We need to rebuild **four** indexes, so you will need to multiply this result
by four to give an estimate of the disk space required. For example, on one
particular server:

```
synapse=# select pg_size_pretty(pg_relation_size('events_order_room'));
 pg_size_pretty
----------------
 288 MB
(1 row)
```

On this server, it would be wise to ensure that at least 1152MB are free.

The additional disk space will be freed once the migration completes.

SQLite databases are unaffected by this change.


# Upgrading to v1.37.0

## Deprecation of the current spam checker interface

The current spam checker interface is deprecated in favour of a new generic modules system.
Authors of spam checker modules can refer to [this
documentation](modules/porting_legacy_module.md
to update their modules. Synapse administrators can refer to [this
documentation](modules/index.md)
to update their configuration once the modules they are using have been updated.

We plan to remove support for the current spam checker interface in August 2021.

More module interfaces will be ported over to this new generic system in future versions
of Synapse.


# Upgrading to v1.34.0

## `room_invite_state_types` configuration setting

The `room_invite_state_types` configuration setting has been deprecated
and replaced with `room_prejoin_state`. See the [sample configuration
file](https://github.com/matrix-org/synapse/blob/v1.34.0/docs/sample_config.yaml#L1515).

If you have set `room_invite_state_types` to the default value you
should simply remove it from your configuration file. The default value
used to be:

```yaml
room_invite_state_types:
   - "m.room.join_rules"
   - "m.room.canonical_alias"
   - "m.room.avatar"
   - "m.room.encryption"
   - "m.room.name"
```

If you have customised this value, you should remove
`room_invite_state_types` and configure `room_prejoin_state` instead.

# Upgrading to v1.33.0

## Account Validity HTML templates can now display a user's expiration date

This may affect you if you have enabled the account validity feature,
and have made use of a custom HTML template specified by the
`account_validity.template_dir` or
`account_validity.account_renewed_html_path` Synapse config options.

The template can now accept an `expiration_ts` variable, which
represents the unix timestamp in milliseconds for the future date of
which their account has been renewed until. See the [default
template](https://github.com/matrix-org/synapse/blob/release-v1.33.0/synapse/res/templates/account_renewed.html)
for an example of usage.

ALso note that a new HTML template, `account_previously_renewed.html`,
has been added. This is is shown to users when they attempt to renew
their account with a valid renewal token that has already been used
before. The default template contents can been found
[here](https://github.com/matrix-org/synapse/blob/release-v1.33.0/synapse/res/templates/account_previously_renewed.html),
and can also accept an `expiration_ts` variable. This template replaces
the error message users would previously see upon attempting to use a
valid renewal token more than once.

# Upgrading to v1.32.0

## Regression causing connected Prometheus instances to become overwhelmed

This release introduces [a
regression](https://github.com/matrix-org/synapse/issues/9853) that can
overwhelm connected Prometheus instances. This issue is not present in
Synapse v1.32.0rc1.

If you have been affected, please downgrade to 1.31.0. You then may need
to remove excess writeahead logs in order for Prometheus to recover.
Instructions for doing so are provided
[here](https://github.com/matrix-org/synapse/pull/9854#issuecomment-823472183).

## Dropping support for old Python, Postgres and SQLite versions

In line with our [deprecation policy](deprecation_policy.md),
we've dropped support for Python 3.5 and PostgreSQL 9.5, as they are no
longer supported upstream.

This release of Synapse requires Python 3.6+ and PostgresSQL 9.6+ or
SQLite 3.22+.

## Removal of old List Accounts Admin API

The deprecated v1 "list accounts" admin API
(`GET /_synapse/admin/v1/users/<user_id>`) has been removed in this
version.

The [v2 list accounts API](admin_api/user_admin_api.md#list-accounts)
has been available since Synapse 1.7.0 (2019-12-13), and is accessible
under `GET /_synapse/admin/v2/users`.

The deprecation of the old endpoint was announced with Synapse 1.28.0
(released on 2021-02-25).

## Application Services must use type `m.login.application_service` when registering users

In compliance with the [Application Service
spec](https://matrix.org/docs/spec/application_service/r0.1.2#server-admin-style-permissions),
Application Services are now required to use the
`m.login.application_service` type when registering users via the
`/_matrix/client/r0/register` endpoint. This behaviour was deprecated in
Synapse v1.30.0.

Please ensure your Application Services are up to date.

# Upgrading to v1.29.0

## Requirement for X-Forwarded-Proto header

When using Synapse with a reverse proxy (in particular, when using the
`x_forwarded` option on an HTTP listener), Synapse now
expects to receive an `X-Forwarded-Proto` header on incoming
HTTP requests. If it is not set, Synapse will log a warning on each
received request.

To avoid the warning, administrators using a reverse proxy should ensure
that the reverse proxy sets `X-Forwarded-Proto` header to
`https` or `http` to indicate the protocol used
by the client.

Synapse also requires the `Host` header to be preserved.

See the [reverse proxy documentation](reverse_proxy.md), where the
example configurations have been updated to show how to set these
headers.

(Users of [Caddy](https://caddyserver.com/) are unaffected, since we
believe it sets `X-Forwarded-Proto` by default.)

# Upgrading to v1.27.0

## Changes to callback URI for OAuth2 / OpenID Connect and SAML2

This version changes the URI used for callbacks from OAuth2 and SAML2
identity providers:

-   If your server is configured for single sign-on via an OpenID
    Connect or OAuth2 identity provider, you will need to add
    `[synapse public baseurl]/_synapse/client/oidc/callback` to the list
    of permitted "redirect URIs" at the identity provider.

    See the [OpenID docs](openid.md) for more information on setting
    up OpenID Connect.

-   If your server is configured for single sign-on via a SAML2 identity
    provider, you will need to add
    `[synapse public baseurl]/_synapse/client/saml2/authn_response` as a
    permitted "ACS location" (also known as "allowed callback URLs")
    at the identity provider.

    The "Issuer" in the "AuthnRequest" to the SAML2 identity
    provider is also updated to
    `[synapse public baseurl]/_synapse/client/saml2/metadata.xml`. If
    your SAML2 identity provider uses this property to validate or
    otherwise identify Synapse, its configuration will need to be
    updated to use the new URL. Alternatively you could create a new,
    separate "EntityDescriptor" in your SAML2 identity provider with
    the new URLs and leave the URLs in the existing "EntityDescriptor"
    as they were.

## Changes to HTML templates

The HTML templates for SSO and email notifications now have [Jinja2's
autoescape](https://jinja.palletsprojects.com/en/2.11.x/api/#autoescaping)
enabled for files ending in `.html`, `.htm`, and `.xml`. If you have
customised these templates and see issues when viewing them you might
need to update them. It is expected that most configurations will need
no changes.

If you have customised the templates *names* for these templates, it is
recommended to verify they end in `.html` to ensure autoescape is
enabled.

The above applies to the following templates:

-   `add_threepid.html`
-   `add_threepid_failure.html`
-   `add_threepid_success.html`
-   `notice_expiry.html`
-   `notice_expiry.html`
-   `notif_mail.html` (which, by default, includes `room.html` and
    `notif.html`)
-   `password_reset.html`
-   `password_reset_confirmation.html`
-   `password_reset_failure.html`
-   `password_reset_success.html`
-   `registration.html`
-   `registration_failure.html`
-   `registration_success.html`
-   `sso_account_deactivated.html`
-   `sso_auth_bad_user.html`
-   `sso_auth_confirm.html`
-   `sso_auth_success.html`