MacOS Sonoma (14)

MacOS Sonoma predates Apple Intelligence entirely, arriving a year before that push began with Sequoia. Its own notable additions were interactive desktop widgets (finally usable directly on the desktop rather than only in Notification Center), a dedicated Game Mode that prioritizes CPU/GPU resources for games, and Safari Profiles for keeping browsing separated by context (work vs. personal). With three major versions now released after it, it sits at the edge of Apple's typical continued-security-update window and is a reasonable candidate for upgrade if the hardware supports newer versions.