About IDX plugin compatibility
IDX plugin compatibility means that the theme works well if you add 3rd party plugins (such as dsIDXpress or Optima Express). The theme will not return any errors just by using these extra options. IDX plugins are Optional and they are not required for the theme to be installed and used.
How IDX Plugins work: If you install one of the IDX plugins, they will work with the theme, without conflicts. BUT the properties added through the plugin can be managed only with plugin features, options. They will NOT be used with the theme options. The properties from IDX are managed in a different database and the theme cannot access those properties (the plugin developers do not offer such access). So you use the plugin as it is, with its own design and features.
For a seamless MLS integration, your properties must be imported into the theme database. Such a solution is available with MLS Import, a 3rd party plugin publishes and automatically synchronizes listings directly with your MLS. Check more info and demos on their website – https://mlsimport.com/
From 1.16 update Wp Residence has a new option in Theme Options for clients who wish to install separately iHomefinder Optima Express IDX plugin. Set the option to YES from MLS – IDX – RESO options.