Strict standards error

I believe this only came up after I upgraded to WP3.9.1 yesterday, but I may be mistaken.

I recently deactivated and then reactivated NextGEN and got the following Strict Standards error messages when I try to reactivate:

Strict Standards: Declaration of C_DataMapper_Driver_Base::define() should be compatible with C_Component::define($context = false) in /homepages/35/path/htdocs/newsite/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/datamapper/class.datamapper_driver_base.php on line 741

Strict Standards: Declaration of C_Lightbox_Library_Mapper::define() should be compatible with C_CustomPost_DataMapper_Driver::define($object_name, $context = false) in /homepages/35/path/htdocs/newsite/wp-content/plugins/nextgen-gallery/products/photocrati_nextgen/modules/lightbox/class.lightbox_library_mapper.php on line 7

WordPress 3.9.1
NextGEN 2.0.65
PHP 5.4.28
MySQL 5.1.73
PHP safe mode is off.
Hosted with 1&1
Using the “Divi” theme from Elegant Themes – theme isn’t the issue as I get the same messages using Twenty Fourteen.

It appears to be a conflict with Xenword – a bridge between WordPress and the Xenforo forum which I’m talking to the developer about. But is there a fix at this end that stands out from the error messages?

Thank you kindly.

Do you have any ideas, please?

https://wordpress.org/plugins/nextgen-gallery/