Why would/n't I "Use older data" for character decomposition?

[eritain]

In settings for the Definition screen Chars tab, there is an option to use pre-3.0 character decomposition data. What is the difference between the old and new? Why do you prefer one or the other?

 

[mikelove]

It's basically there for people who liked the data before 3.0 - quite a few options (which we need to do a better job of getting out of the way for newer users) exist essentially for the sake of people who started using Pleco at some previous point in time + would have their workflow badly disrupted by a particular change if we didn't provide a way to reverse it.