24.04 LTS needs pro for complete upgrade?

[guiverc]

Ubuntu Pro includes two items

• includes ESM or extended security fixes which start when standard support has ended; ie. 5 years after initial release
• includes optional security fixes on packages in the universe repository; as only main and restricted get security fixes on a normal install.

The additional updates you’re seeing are in my second item, as Ubuntu has historically only provided security fixes for packages in main and restricted. By enabling Pro, you’re getting the optional fixes available for packages in universe too.

The flavors (Kubuntu) are community based, and we don’t get coverage from the Ubuntu Security team (I’m a member of the Lubuntu team) [without Pro].

SecurityTeam/FAQ - Ubuntu Wiki

Ubuntu Pro - FAQ

This document was prepared in collaboration with Ubuntu community leads. Executive summary Your Ubuntu LTS is still secured in exactly the same way it has always been, with five years of free security updates for the ‘main’ packages in the distribution, and best-effort security coverage for everything else. This has been the promise of Ubuntu since our first LTS in 2006, and remains exactly the same. In fact, thanks to our expanded security team, your LTS is better secured today than ever befor…

https://ubuntu.com/security/esm

You’re not using the latest version of Kubuntu, that’s Kubuntu 25.10 or the 2025-October release, with 24.04 being three releases before that latest release.

You may be confusing ESM & Pro, as its ESM that starts when standard support ends (Pro has benefits during the standard support years as you’re discovering).