So I got both versions on my computer and I started to compare them and after some debuging I can tell you where does the problem come from.
includes/public/class-wprm-template-manager.php
So right now I have 1.4.0 installed and it does not work. If I overide the new class-wprm-template-manager.php file (v 1.4.0) with the old verstion of class-wprm-template-manager.php (v 1.3.0) the website works.
But guess what, I digged even further. I kept the entire 1.4.0 version and I started to make changes only in class-wprm-template-manager.php putting old code back one by one and I managed to find out where it fails.
It’s inside function get_template more exactly at this line:
return do_shortcode( $template );
So the conclusion is this: Version 1.4.0 doesn’t work for me only if I replace:
return do_shortcode( $template );
with
return $template; (like it was in the previous version)
If I do this, the website works again. I don’t know what should do this do_shortcode function, I haven’t checked, but I know for sure that in my case it does not work because of this.
As I can see do_shortcode is a wordpress function, I don’t know exactly what it should do but this is the problem, so what do you say about this?