Please be aware that Microsoft has officially ended support for Windows Phone. Additionally, UCWeb has stopped updating the Windows Phone version of UC Browser. This means:
Back in 2015, installing the XAP via the SD card trick was simple. Microsoft has shut down the Windows Phone Store and activation servers. Unless you already have the XAP file saved and a pre-unlocked Lumia, you cannot legally or easily install this. uc browser xap
If you can’t find a working UC Browser XAP, try these instead: Please be aware that Microsoft has officially ended