Version 5.7.1 was optimized for its era, handling RAW files from older DSLR cameras efficiently. On modern high-resolution monitors (4K/5K), the interface can appear dated or small.

Lightroom 5.7.1 was the final update to the perpetual license version of Lightroom 5 before Adobe transitioned fully to the Creative Cloud subscription model. Because it is over a decade old, it is considered software. If You Already Own a License

If you purchased a digital download, search your inbox for an order confirmation from Adobe containing the license key. Important Considerations for Version 5.7.1 Just wondering how I input my serial number into LR 5

Still Using Lightroom 5.7.1? Everything You Need to Know About Serial Keys and Support