Fatal error on 1.8.4 with Uncode theme

This plugin is usually installed as a recommended plugin with the Uncode theme, however version 1.8.4 is causing a fatal error.

This appears to be because the theme is using the “TO_apply_order_filter” filter which can no longer be found.

PHP Fatal error:  Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, function "TO_apply_order_filter" not found or invalid function name

Other custom code might be using this filter as well.

Would it be possible to reinstate that filter to prevent fatal errors when the plugin is updated?