I appreciate a good success story about major transitions / upgrades / process changes / etc. Those situations where there is usually SOME glitch and you have

I appreciate a good success story about major transitions / upgrades / process changes / etc. Those situations where there is usually SOME glitch and you have to engineer the hell out of it to get a perfect transition. The only reference to testing was "We had the Codec tested for both safety and EMC." Was that in house or external? Surely there was some major transition testing low power broadcast tests, etc to make sure everything went smoothly. Or did they just get really lucky? Seems like there's more story to this.