Hi, I am one of early user of RN4 MTK China since I bought a month after its release.
I used it as it is and never bother to change ROM and did not reset even once. So lazy to do data backup

This phone served me well during these 2 years until recently the battery drain getting worse and the % become so erratic that in can goes up and down in a single charge

Few days ago finally I decided to do complete wipe and flashing latest global ROM V9.2 while at it and I am glad that I did. Feels like owning a new phone now... I think I can keep it for at least another year if nothing broke.

This morning I received OTA V9.5.1.0, looks like a lot has been improved looking by the changenotes.

what problem and how bad is it?

My 1.5years old rn4 still hold the charge at least 1 whole office hours as I use it extensively.

My mtk version still on 9.5.2.0

This is very true. At least before think to replace the battery, try do a full flash rom first. Some dodgy app and games are the causes from running ads in backgound, wakelocking the phone, etc..

I can't remember when was the last time I got OTA updates for mtk version. I guess this model reaching its end of life already. 3 years is good enuff for midrange

Uhm yes..? aug '16, aug '17, aug '18... its the 3rd year now. I am sorry if my understanding is wrong.

Then again I did enjoy using this cheap mtk one, so far only did full format once but the performance still like new since 2016 except degrading battery life which is like every other phones anyway.
It's a phone I keep using the longest now, as usually I change new every year as the phone failed. My Moto suddenly dead on me (1 year+ usage), before that my xperia within a year become annoyingly lag so much no matter how many times i reformatted.

So as a midrange user, RN4 mtk for me alone is a damn good buy despite its lesser updates.

Hi, I have been there. The battery % became so erratic like every minute drop 1-2% until 0% shutdown itself then after restart got like 20% again.

I did fully deplete the battery until cant reboot anymore then full charge without on, made few cycles of that only start better each time. While at it I flashed global rom, then problem solved without replacing the battery itself. But yeah it wont last full day like new set anymore.

bootloop. try go safe mode and clear cache 1st, if not works then clear data to format but bye2 your data.