Download U221 005 Apr 2026

If the output does not explicitly mention "64-Bit," you may have the 32-bit version installed, which can limit performance or cause startup failures for certain applications. Where to Download

: Users often seek this specific version when newer Java updates cause "Starting UniFi Controller" loops or other compatibility issues with older network management software. Troubleshooting Tip Download u221 005

Official legacy downloads are hosted on the Oracle Java Archive , though these typically require an Oracle account. For community-driven troubleshooting and alternative download paths, many users reference the Ubiquiti Community forums for specific configuration advice. If the output does not explicitly mention "64-Bit,"

The identifier (or U221 ) commonly refers to specific builds of Java 8 Update 221 , a legacy version often used for maintaining compatibility with older software like the UniFi Controller or legacy enterprise applications. Technical Overview Version Details : Java 8 Update 221 (Build 1.8.0_221-b11). : Available for both Windows (32-bit and 64-bit)

: Available for both Windows (32-bit and 64-bit) and Linux systems.

If you are installing this to fix a controller issue on Windows, ensure you are using the if your operating system is 64-bit. You can verify your current version by opening a command prompt and typing: java -version