I installed the android 10 update two days ago. I checked the led notification and the edge lighting. They both appear when the screen is off and locked. I tested using Samsungs messages, Gmail, and others. I hope the next update brings these features back to your phone.
Galaxy S9 SM-G960U
Security Patch Level
February 1st 2020
I used an app to prevent my phone from updating but unfortunately my wife's phone slipped through the cracks and she received the update.
The missed call notification light, which used to blink green DOES NOT WORK any longer. Check your phone.
Tried all common troubleshooting procedures.
Samsung should fix this but will not ignore it. All of a sudden my wife envies the S8 users for not being forced into the update.
I will NEVER understand why the OS update is FORCED. My phone, my decision. This is absolute crap
From what I have discovered. This issue only happen in unlocked phones. My friend has the same phone from ATT locked post paid & has no isses. I also have ATT unlocked on pre paid. The only way I was able to get the led to work for messages was to turn on Edge lighting still does not work for missed calls, voice mail or emails. Defintley a code issue & Samsung needs to send out a new update to fix this issues. I as well do not like to update to a new version but my friend did with out a hitch so I did the same & I regret it!!
My wife's phone is a Tmobile phone. Ironically, they were one of the last to push the update. Then they paused for a couple of days, for an unknown reason. Then they started to push the notification again.
My biggest gripe is that, there is no option given to the OWNER of the phone to decide to upgrade.
If given option, then you can decide if you want to upgrade with the known issues or the sacrifices.
My wife has an S9 and was facing this issue from few weeks. I tried fixing it by copying same notification settings as were on my S9+. But instead lost my own indicator light notification in the process (which was working fine earlier). Its definitely a bug in One UI 2 update.
I am from India.