I have the problem on my local server running 5.3.8 and a prod server running 5.3.24, and version 2.2.4 of the plugin. (2.2.3 works)
I don’t think it’s a __DIR__ issue, the file
/wp-content/plugins/simplr-registration-form/lib/sreg.class.php
does not exist in the install.
The message I get is:
Warning: require_once(/home/<path removed>/wp-content/plugins/simplr-registration-form/lib/sreg.class.php) [function.require-once]: failed to open stream: No such file or directory in /home/<path removed>/wp-content/plugins/simplr-registration-form/simplr_form_functions.php on line 439
Line 439 is looking for that file:
‘require_once __DIR__.’/lib/sreg.class.php’;’