When there is a plugin update, but it's incompatible with the currently used SQ version, there is no "Update" button. The only chance to understand why is to put the mouse over the orange version badge to see "Requires system update". This might be not enough.
Instead we should display a disabled "Update" button, so users understand that the update is available, but blocked by some condition. The tooltip should say something like "This plugin version requires SonarQube <required_version>".