You do not need a separate download link; it is accessible through the "Betas" menu in your game launcher: Steam: Right-click Stardew Valley in your Library. Select Properties > Betas.
Update: Steam will automatically begin downloading the legacy version. How to Download on GOG Stardew Valley Compatibility Version Download
Select Branch: In the "Beta Participation" dropdown, choose compatibility. You do not need a separate download link;
Furthermore, there is an ethical consideration regarding the developer. ConcernedApe is known for his generosity, providing free, substantial updates years after release. By sticking to older compatibility versions, players technically fragment the community and delay their support of the "official" vision of the game. However, most players view this as a temporary necessity, eventually migrating to the latest version once their essential mods are updated. How to Download on GOG Select Branch: In
For handheld users, the compatibility version is often required to get the game running. Set Steam to the "compatibility" Install/Reinstall Stardew Valley in PortMaster. Copy the updated game files from your PC Steam folder ( steamapps/common/Stardew Valley ports/stardewvalley/gamedata folder on your SD card. Stardew Valley Compatibility Guide