The latest version is probably 5.1.0, but I doubt it will affect your problem.
It seems that it may be an error on the ewelink infrastructure side…
Unfortunately, as an ordinary user, I am not able to help here. 
I suggest creating a ticket or sending appropriate feedback via the ewelink app. On the forum you may not receive official help quickly or at all… it varies, so in case of serious problems you should always use official support channels.
I recommend creating a ticket in English with the above information and reporting this matter to support.
Launch the app and go to Profile / Help & Feedback / Feedback / Submit Feedback
or… 📣 Please raise your ticket via the help center if help needed