While updating Android Studio (2020.3.1) to patch 4 as root (since it was recommended to do so), I also updated the Kotlin plugin (to 1.6), since I was prompted to do so immediately after clicking "OK" to install patch 4.

The version number for the Kotlin plugin when running as root is 1.6, though is still 1.5 for user. Marketplace shows 1.6 as being installed for both user and root.

Kotlin Plugin version for root (1.6.0)

Kotlin Plugin version for user (1.5.20)

Marketplace for both user and root

Also, 'plugins/Kotlin/kotlinc/build.txt' shows

1.5.20-release-289

This was the first time that I have ran Android Studio as root. I chose not to import any settings, and cancelled the setup wizard since it would've required a separate download of the SDK and other things that I didn't need.

The Kotlin plugin for root was installed to

/root/.local/share/Google/AndroidStudio2020.3/Kotlin

The 1.6 update eventually became available to user, and seemingly installed without issue.