I no longer use an iTouch. When I had one, this was a common occurrence when the app was updated.
My upgrade checklist looked something like this. I would try to restart it several times. I would reboot my device and then try several times to start the app. I would remove the app and reload it. Even then, it sometimes took multiple attempts to get it to start and work. Each time it seemed it got a little farther before it crashed, and after a few tries, it was working again. Sometimes.
And I would always, always send an email to the developers when I had a problem. If I could not get the app working far enough to send the bug report, I would type the address into my email client and send the report.
When the iOS changed and a new version of the app was released, I was usually out of luck. It seems when LDS Tools is revised for a newer iOS, it no longer works well (or at all) with an older iOS. I do not believe that is the fault of LDS Tools. I think it just has to do with how the operating system works.
My stake president had an iPhone with an old iOS and could not use much of LDS Tools at all after one of the upgrades until he bought a new phone a year later. It was a long year, especially for him. He did not need a new phone. The one he had worked perfectly fine. But the iOS had moved on and left him behind. And LDS Tools had moved to the new iOS.