This thread is resolved. Here is a description of the problem and solution.
Problem:
The issue here was that the user was getting the error.
PHP Fatal error: Can't inherit abstract function Types_Interface_Value::get_value() (previously declared abstract in Types_Field_Part_Interface) in /var/www/html/wordpress-multisite/wp-content/plugins/types/application/models/field/part/option.php on line 8,
Solution:
This issue was actually resolved in our Latest version of Types and I would recommend that you update to this version.
This support ticket is created 6 years, 6 months ago. There's a good chance that you are reading advice that it now obsolete.
This is the technical support forum for Toolset - a suite of plugins for developing WordPress sites without writing PHP.
Everyone can read this forum, but only Toolset clients can post in it. Toolset support works 6 days per week, 19 hours per day.
Actually this is a feature of our Toolset Types 3.0 with the new relationship model. In order to get this feature you will need to install our version 3.0 of types.
I upgraded to the new version, but now my page is all messed up : hidden link
Server log :
[Thu Jul 19 11:53:14 2018] [error] [client 128.59.197.44] PHP Fatal error: Can't inherit abstract function Types_Interface_Value::get_value() (previously declared abstract in Types_Field_Part_Interface) in /var/www/html/wordpress-multisite/wp-content/plugins/types/application/models/field/part/option.php on line 8, referer: hidden link
As per our requirements page this should be compatible with toolset as a bare minimum but I would honestly recommend at least version 5.6 because i've seen where 5.3 has caused issus such as slowdowns and crashes so I would recommend at least version 5.6 or higher.
This is also maintain compatibility with the wordpress core as well which recommends at least php 7