How to fix W: Conflicting distribution: URL InRelease (expected codename but got codename) in APT

Run:

lsb_release -cs

This displays your Ubuntu/Debian version codename (e.g., 'focal', 'jammy', 'bullseye').

List your APT sources:

grep -r '^deb' /etc/apt/sources.list /etc/apt/sources.list.d/

Compare each codename against your actual system codename from step 1. Look for entries that don't match.

Edit /etc/apt/sources.list:

sudo nano /etc/apt/sources.list

Replace the old codename with your current one. For example, change:

deb http://example.com/ubuntu focal main

to:

deb http://example.com/ubuntu jammy main

Save with Ctrl+O, Enter, Ctrl+X.

Check for third-party repository files:

ls -la /etc/apt/sources.list.d/

Edit any files with old codenames:

sudo nano /etc/apt/sources.list.d/microsoft-ubuntu-*.list

Update codenames in these files as well.

If you need updates immediately, allow APT to accept the codename mismatch:

sudo apt update --allow-releaseinfo-change

This is a workaround; proper fix is updating sources.list to match actual codenames.

Run apt update without warnings:

sudo apt update

The warning should no longer appear if all repositories now match your system's codename.