Updater stuck at “Updater is loading.” (3.4.5 - > 3.4.7)

Hi, I’m trying to updated phpList 3.4.5 to phpList 3.4.7 but it gets stuck.

If I open the browse console I get the next error:

steps[stepActionMap[setp]] is undefined


A quick search on the forum will find a number of similar posts, many with solutions or guidance.

I have already read and applied all the tips but any work for me. I have to use the production environment code in order to update my QA version and it work.