Help needed Updating ZE551ML. Rooted.

I have a rooted 64 GB Zenfone 2 (ASUS_Z00AD) with WW_2.20.40.174_20160310. I am experiencing some battery ans WiFi dropping issues so I just found that there is an update available on ASUS website - Version WW_2.20.40.184. I want to update it without loosing my data. What steps should I use? I just want to update hoping it will fix the issues that I have with my phone. The most important thing is I dont wanna loose my data.

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