Working good for me.

[digitalcuriosity]

I upgraded it to my new iPhonePlus soon after buying the phone and as of 09/28/2018 it is working good IMHO.

 

[rossboyer]

Mine Isn’t
I connect to my HP printer via WiFi and OS 12 disconnects every 25 seconds and then reconnects. OS 10 & 11 worked fine

 

[digitalcuriosity]

Mine Isn’t
I connect to my HP printer via WiFi and OS 12 disconnects every 25 seconds and then reconnects. OS 10 & 11 worked fine

Have you contacted HP support i had this happen with an HP printer also an Epson printer, not via a phone but still it was a printer software problem.
Also you can contact Apple support support at 1-800-692-7753 i have called them many times and have been given quality help each time.
Also check that your Router's software is up to date, many times it's not and can cause connecting problems.