Canonical: up to 12 years of support for Ubuntu 24.04 LTS - gHacks Tech News
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Core support for Ubuntu won't change according to Shuttleworth. Ubuntu LTS versions continue to be supported for 5 years and non-LTS releases for 9 months. Ubuntu 23.04 is the current release version, Ubuntu 22.04 LTS the current long-term support release.
Ubuntu Pro subscribers may extend support of LTS versions by an additional 7 years going forward. Ubuntu Pro is available for Home users and Enterprise / business customers. The subscription is free at the time of writing for Home users and starts at $25 per year and machine for Enterprise customers. Server subscriptions start at $500 per month.
I find this very exciting though as it matches Redhat's support length and should allow you to basically install 1 supported OS for the lifetime of a machine