Question: How do I turn off the developer log? 

I already checked the **Output and Debugging Preferences** at the **System administration** section in the CMS but there's no option for that.

Answer: 
Can you try by setting within config file:

```
$config['log_threshold'] = 0;

```

Sorry, I didn't try it so not sure if would work for you.

===

The "log\_threshold" setting is detailed here in the docs:  

<https://ellislab.com/expressionengine/user-guide/general/system_configuration_overrides.html#log-threshold>
I assume you mean the the notice the appears when there are notices for developers, on the control panel home screen?

AFAIK, you cannot disable the Developer Log. But these notices should only be showing to Super Admins.