Today we got a new update to Twitter app for android.
The new update brings a new feature to the app. This is very old requested feature which is ‘Night Mode’ . The night mode can be enabled by thw Hamburger menu of the Twitter app for Android.
— Twitter (@twitter) July 26, 2016
Currently the night mode feature works manually. You have to toggle the mode to ‘On’ in order to use the feature. The company may introduce automatic switching into night mode on further updates.