I have just noticed that all passes added to Passbook/Wallet on iOS9 have, by default, the option "Suggest on Lock Screen" disabled, while on iOS8 they were enabled.
And I have noticed that passes added from apps have the option enabled while passes added via QR code does not.
Does anyone know if possible to add any configuration to the pass.json in order to enable the suggest on lock screen for a specific voucher/pass?
I cannot find any information about it.
Thanks
As of my knowledge, this is not for the developer to change, however the user has to enable that himself/herself. Therefore to answer your question, no it is unfortunately not possible to change anything in the pass.json to automatically enable or disable the show on lock screen.
If you want to find out more about Apple's Wallet, you can check it out here or watch the video from the WWDC 2015 here.
I found a few more links for you that may help regarding Passkit and passes.
Here you can find a great tutorial on creating passes.
Here you can find the Web Service (server) reference provided by apple.
Here you can find the complete guide from Apple and last but not least, here you can see the PassKit framework reference.
Hope that helps better now, Julian