Thanks for the great words.
1) Is it possible to display the add to homescreen banner of your plugin to iOS browsers like chrome or safari? I′ve tested my site and your site and there is no banner displayed. I′ve installed iOs 11.3 and pwa works generally.
The Add to Home screen prompt is not available right now on iOS devices as Apple just started supporting PWA from the version 11.3. Most probably we can expect an inbuilt prompt like on Android devices on coming versions of iOS.
2) At android I cannot see any more any add to home screen banner on your page and on my page. I′ve added a pwa of my page yesterday successfully and deleted it again. Now I the banner doesn′t show up. I′m using lineageos on oneplus 2 at chrome. I′ve deleted all cache.
Upon Android the Add to Homescreen prompt will only occur once, until the cache get cleared on Browser. Here’s the steps to easily troubleshoot:
1) Can you please let me know whether you have installed the PWA earlier for the same website on your device? If yes, please uninstall and clear the cache. You can easily check this by tapping the browser menu (the three dots at the right corner of your Chrome Browser), if its added earlier you can see “Open _____” there, otherwise it will be “Add to HomeScreen“.
2) Can you please let me know whether you have cleared the browsing data on browser?
Here’s the steps to clear the browsing data by tapping the browser menu on Google Chrome for Android > Settings > Privacy > Clear browsing data > Select Advanced tab > from that select options like Browsing history, Cookies and site data, Cached images and files, Site settings and tap Clear Data.
3) Can you check any other PWA website’s (you can check our website superpwa.com) and let me know whether the Add to Home screen prompt occurs or not on your browser? If not, its because of the low memory storage limit within your device for browser. Free up some space and clear the cache to test it again.
Looking forward to hear your thoughts.