Missing find my friends app

i have the iPhone XS Max, I’ve done the IOS update this morning and since then my ‘find my friends’ app has disappeared. It no longer shows up in my App Store and when I search for it in my phone, a message comes up saying it’s not compatible on my phone. A friend has an older phone than me and my hubby has just got the 11 and both of them still have it. I’m frustrated as I need it to keep an eye on my son when he goes out. Any ideas?