Yes.
I use Simplex, too, but it's hit-n-miss.
Discussion
That’s why I uninstalled it. I was never sure if my recipient actually got the message.
Do you know if you send a link (pointing to an image), like if I copy the url from an image on nostr and send it via threema, does it render the image or does it just show the link ?
I think, just the link. Not sure.