Three weeks ago, Apple was holding court at the San Jose Convention Center, where it kicked off its annual developer conference with first looks at iOS 13, iPadOS and the latest version of macOS, Catalina. Today the company is releasing Catalina in beta, though I've been testing it since last week. This time around, the story is mostly about Apple's first party apps, many of which have received an iOS-inspired overhaul. Speaking of the sort, it's been a year since Apple announced it was working on a framework designed to make it easy for developers to port iOS apps over to the Mac; first-party apps from last year's macOS Mojave release were even built on this technology. Twelve months later, Apple opened that development kit to third-party programmers, so we're finally seeing mobile-first apps adapted for Macs' larger screens. With this release, Apple also included a feature called Sidecar, allowing an iPad running iPadOS to be used as a secondary screen for mirroring or extending a Mac display.