iOS 11.4.1
Just a quick bit of background. There may be two separate issues in this thread (leaving aside irrelevant issues). The original issue was that iOS 11, from its launch last autumn, caused severe streaming problems with some hearing aids; it became clear later that recent model hearing aids were working fine with iOS 11 and that only those of us with older models seemed to have problems. (Mine were only a little over 3 years old.) If I understand other posts correctly, iOS 11.4 seems to have introduced MFi streaming problems specific to iPhone SE. I'm an iPhone 8 user, so can't comment on the SE issue. Because streaming is very important to me (I also use VoiceOver, the talking interface for the blind), I reluctantly decided to buy a new pair of hearing aids, Resound Linx 3d and these have worked fine with all versions of iOS 11 since I acquired them. I upgraded to iOS 11.4.1 yesterday from iOS 11.4 and the Resound Linx 3d continued to stream well, so there was no regression due to iOS 11.4.1.
Today, I took the plunge, instructed my iPhone to forget the Linx 3d aids, put fresh batteries in my old Linx 9 hearing aids and - they may be a little better, but performance is still erratic. It takes over ten seconds for both aids to start streaming (streaming starts with just one aid in my tests today) and I've experienced disconnections with streaming reverting to the iPhone speaker. I did have one good music streaming session, but, on the whole, if there is an improvement, it's by no means a total fix and certainly doesn't offer acceptable performance.
Maybe it will work better for some other manufacturers' older hearing aids.
Others, please try the update and let us all know what your experience is.
My conjecture it that Apple's message that iOS 11.4.1 fixed MFi hearing aids bugs was sent to me in error and that they were referring to the SE-specific issue. So, perhaps, SE owners will find their problems solved? Of course, it may also be that iOS 11.4.1 doesn't contain the hearing aids fixes that were in the beta. There is certainly no mention of hearing aids fixes in Apple's release notes.
Brian