synapse/docs/modules/porting_legacy_module.md

# Porting an existing module that uses the old interface

In order to port a module that uses Synapse's old module interface, its author needs to:

* ensure the module's callbacks are all asynchronous.
* register their callbacks using one or more of the `register_[...]_callbacks` methods
  from the `ModuleApi` class in the module's `__init__` method (see [this section](writing_a_module.html#registering-a-callback)
  for more info).

Additionally, if the module is packaged with an additional web resource, the module
should register this resource in its `__init__` method using the `register_web_resource`
method from the `ModuleApi` class (see [this section](writing_a_module.html#registering-a-web-resource) for
more info).

The module's author should also update any example in the module's configuration to only
use the new `modules` section in Synapse's configuration file (see [this section](index.html#using-modules)
for more info).