Advice for deploying to iOS from cloud build

Hi, At the moment I'm building a game on Unity Cloud Build. I'm building using Unity 5.3.4f1. My current editor version is 5.3.4f1. This version has preloader launch problems - i get

 Thread 30 name:  UnityPreload
 Thread 30 Crashed:
 0   imonster                          0x014511f4 0x3c000 + 21058036
 1   imonster                          0x014513dc 0x3c000 + 21058524
 2   imonster                          0x01454724 0x3c000 + 21071652
 3   imonster                          0x0142a0c4 0x3c000 + 20897988
 4   imonster                          0x0128ca14 0x3c000 + 19204628
 5   imonster                          0x0128d72c 0x3c000 + 19207980
 6   imonster                          0x0126719c 0x3c000 + 19050908
 7   imonster                          0x01264ff0 0x3c000 + 19042288
 8   imonster                          0x01264e34 0x3c000 + 19041844
 9   imonster                          0x01264df0 0x3c000 + 19041776
 10  imonster                          0x012ba150 0x3c000 + 19390800
 11  libsystem_pthread.dylib           0x226dcc7f 0x226da000 + 11391
 12  libsystem_pthread.dylib           0x226dcbf3 0x226da000 + 11251
 13  libsystem_pthread.dylib           0x226daa08 0x226da000 + 2568

When trying to launch the game. Which is fine... So i've started to try the rest of the available versions on this level... 5.3.4p's... which go all the way up to 5.3.4p6... And have noticed the stencil shader starting to break and inconsistencys between my iphone 6 and my friends iphone 4 (UI is not showing on his phone) as i've traversed these... and still haven't found a stable spot for both of us. I'm just wondering what the smartest way to deal with this stuff is. Is there a known stable version of Unity which I can hop to?

Its just, this isn't the first time this is happened - and it feels like finding the right version of Unity is abit like playing whackamole...

If anyone has any general advice, or perhaps insight into what i might be doing wrong in processes I'd love to hear it.

To be clear, i'm not changing my version of Unity. I'm just changing the built version of Unity on Cloud build... I'm guessing this might be a no-no...