Cannot enable / connect to peers with older iOS (12.x)

[paulreimer]

I cannot seem to get some older iPhones (iPhone 5s/6s; iOS 12.5.5) to work with the Testflight app (v0.1). Toggling the "Enable" switch doesn't establish a connection; I see no attempt to connect to my selected peer (in the peer's yggdrasil service's logs).

The "Enable" switch appears to be in the ON state, but any scrolling in the iOS view immediately re-renders the switch as OFF. None of the other info fields change at all -- not even briefly.

I've tried with three different iPhones at this version; meanwhile more recent iPhones with iOS 15.x connect to my target peer(s) with no issues. I have tried some public peers, as well as a peer that I run -- both with and without AllowedPublicKeys set. Multicast peers are also present and working on my home network, but it doesn't appear to connect to those either.