A. Apple has been building operating systems and Mac hardware with 64-bit processors for years now, and is indeed moving away from 32-bit desktop software too. (The terms “32-bit” and “64-bit” refer to the more technical side of computing; a basic thing to remember is that 64-bit systems are newer and can process more data faster.)
At this year’s World Wide Developers Conference in June, the company announced that all new programs submitted to the Mac App Store starting in January 2018 must have 64-bit support. Starting in June 2018, updates from developers for their existing programs must also provide 64-bit support. With all apps in its store written for 64-bit systems, Apple will begin to phase out its own support of 32-bit programs.
Apple also announced the macOS High Sierra operating system previewed at the conference this summer will be the last system to run 32-bit apps “without compromise.” The final release of High Sierra is expected this fall.
In the System Information area of your Mac, you can see which of your installed apps are 32-bit versions and which ones are 64-bit. To get there, go to the Apple Menu in the top-left corner of the screen, select About This Mac and click the System Report button in the box. (As an alternative shortcut, hold down the Option key when you click the Apple Menu and choose System Information.)
On the left side of the box, find Software and click Applications. The Mac may take a few minutes, but it eventually rounds up a list of programs installed on your computer. Open the box until it is wide enough to see the “64-bit” column and then read down the list to see if each app is designated as “Yes” or “No.” The “No” apps are the 32-bit programs that you will need to eventually update or replace in macOS updates that come after High Sierra (probably beginning in 2019).
Mac desktops and laptops have used 64-bit Intel processors as the standard for about the past decade. Apple’s site has a list for those who want to check the type of processor they have.