Can the app be used offline (without internet or data)?

The only way a user can download an iOS app without internet is if iTunes has been synced to the device. Otherwise, the user will absolutely need an internet connection to download your app, for both the iOS and Android versions. 

The very first time the GoodBarber app is launched, there must be an internet connection in order for the content to be initially loaded and cached. 

In order to see all elements of a page without internet, each piece of content must first be opened while connected.
For example, if a user enters an "Articles" section while connected, but only opens 2 out of 10 articles, these 2 are the only ones they will be able to revisit later on without internet. 

The content cached during a session will later be available for viewing without an internet connection. For any future update you make or any new content you publish, the user will need to be connected to view these updates. 

-Articles section, for instance: CMS Blog, WordPress sections etc...

-Photo, for instance: Gallery, Flickr, Facebook photos, etc... 

-Maps, for instance CMS Map or Kml sections

-Calendar, for instance CMS Calendar, Google cal, iCal/vCal

-Podcasts (Only if the content has been saved as a favorite, it can be accessed offline from the Favorite page)

-Social media sections

-HTML (only if the HTML template is used)

-Click-to sections that are phone numbers

-About

-Click-to sections directing the user to a website or email address (they can write and save an email as a draft, but not send it)

-Sound sections  (except Podcast, see paragraph above)

-Live Audio, Live Video, Live Plus

-Videos

-Form

-Submission

-User Authentication cannot be used offline

Push notifications can still be sent to offline users, but will be stored in the user's notification center and only available for viewing once they have connected to the internet. 

Statistics are still collected regardless of the connection status, so don't worry about missing out on this data. 

Offline functionality in PWA's is possible thanks to a cache management system.

On iOS, the data storage is limited to 50Mb, but not on Android.  

On Android, the stored files are deleted if there's no storage space left. On the other hand, on iOS, if the user hasn't used the PWA in several weeks, the cached files are deleted. The data is re-downloaded when the PWA is opened again.