Thank you for your reply!
Why do you think there must be quotes? ProcessWire is happy with booleans and integers. Even the core-modules are written in the same way:
return array(
'title' => 'Text',
'version' => 100,
'summary' => 'Field that stores a single line of text',
'permanent' => true,
);
from wire/modules/Fieldtype/FieldtypeText.module
When do you get this warnings? I cannot reproduce that (with E_ALL enabled in php.ini).
Which PHP Version did you use? With my Version 7.0.28 everything seems to be fine.
Greetings Sebi2020