Tip: We generally recommend upgrading to the latest Iguana release, unless there is a specific reason not to.
Upgrades should always be tested first in a non-production environment, this is particularly important for large mission critical systems.
There is no benefit what so ever in moving from Iguana 3.x to 4.5 instead of moving straight to Iguana 5.5.
Iguana 4.5 was released about a month before Iguana 5.5 was released.
Essentially the only difference between Iguana 4.5 and 5.5 is the global dashboard and the Translator.
Now don’t get me wrong – the Translator is huge! But if you are highly risk adverse you have a very simple solution. Just don’t use the Translator components. Done. It’s that simple.