@Colleen253
Haha, I've missed the “spangly-ping” sound too, and wonder if I'll ever hear it again, given that my calendar is blocked!
I've asked my tech-savvy pal with an iPhone if she thinks my workaround is do-able because I think it should be... albeit with a bit of faffing... I mean, it's basically about downloading a ringtone to your phone and then assigning that as a text message tone to Airbnb in your contacts book... Surely the iPhone people haven't banned that!
Oh, I'm not great at explaining tech stuff – just chuck your phone over here and I'll do it for you 😉