This is safe but I just checked now and unfortunately latest OTA zip file is not provided yet.
Also you can use SPFT and flash complete ROM
Please read full instruction and warnings.
Here is SPFT instruction http://community.umidigi.com/thread-16931-1-1.html
To save user data please uncheck user data.
Here you have all available ROMs http://community.umidigi.com/forum-178-1.html