Downloading specifically is difficult because Apple officially only sells and distributes the current version of the software. However, if you have previously purchased Final Cut Pro, you can often download the "last compatible version" for your specific Mac's operating system through the Mac App Store. How to Download the Last Compatible Version
If you already own a license, you can access older versions through your account: Open the . Click on your name/profile icon in the bottom left corner. Locate Final Cut Pro in your Purchased list. final cut pro x 10.3.4 download
Finally found a working archive copy of Final Cut Pro X 10.3.4 (Legacy install) Click on your name/profile icon in the bottom left corner
Released around early 2017, the 10.3.4 update was primarily focused on stability and refining the dramatic interface overhaul introduced in 10.3. final cut pro x 10.3.4 download
10.3.4 is noticeably faster on old Mac Pros (2012 cheesegrater) than 10.4+. But it lacks proxies, closed captions, and advanced color tools. Only use for legacy timeline repairs.
Apple occasionally hosts combo updates and specific professional application support files on their official support downloads page. Check the official Apple Support site for standalone installer updates if you already have the base 10.3 software installed. A Warning Regarding Third-Party Sites