The most significant change in 10.13 was the introduction of the as the default for Macs with all-flash storage.
: Optimized storage by using up to 35% less disk space and introduced "Top Hits" in search results to surface the most relevant emails. Technical Specifications macOS High Sierra 10.13 (17A365)
Technical Overview: macOS High Sierra 10.13 (Build 17A365) macOS High Sierra version 10.13 (Build 17A365) was officially released on September 25, 2017. Positioned as a refinement of the preceding macOS Sierra, it focused heavily on "under-the-hood" performance improvements and architectural updates rather than aesthetic overhauls. System Core & Architecture The most significant change in 10