Looks like it's crashing in the stroke order box - must have been some change in how they handle the setup of offscreen views. (odd that they'd update you to 5.0.2 when 5.1 is already out)
Anyway, we'll fix that in 3.2.20 but in the meantime it's unlikely an old version would help so instead I would suggest that you delete the stroke order database (so that it won't try to add the stroke order box to the screen). To do that, use a file manager to go onto your memory card, go into /Android/files/com.pleco.chinesesystem/modules/ and delete the folder "10007801."
Just wanted to say that, even before the latest update of Pleco, there has been an update of Multiling O, and the issue is now resolved. At least I think that is the case because I had not updated Pleco in a couple of days, but there have been one or two updates of Multiling O in the meantime. And it definitely worked again before I updated Pleco to 3.2.20.I have a problem with handwriting input since updating: The suggestions in the input field do not get cleared anymore, so with every new stroke I enter, the new suggestion is added after the previous instead of replacing it. The same also happens when I select another character from the list of suggestions at the bottom. For example, if I write the character 真, I end up with "一十十冇百南直真真" in the input field.
I had updates of Multiling O as well, but for me the problem didn't disappear until the workaround was introduced in the last Pleco update (thx btw ).Just wanted to say that, even before the latest update of Pleco, there has been an update of Multiling O, and the issue is now resolved. At least I think that is the case because I had not updated Pleco in a couple of days, but there have been one or two updates of Multiling O in the meantime. And it definitely worked again before I updated Pleco to 3.2.20.