If the XML-RPC option within the WordPress System Lockdown feature is disabled, you should be aware of the certain implications.
Here's what may be affected on your WordPress sites:
- Certain JetPack plugin functionality will be impacted.
- The mobile Android/IOS apps will be broken with your site since they run over the XML-RPC system.
- Any other system or plugin that uses your site’s XML-RPC system to communicate and operate your site.
For more information about the XML-RPC system, read the blog article here.