The tag is the digital fingerprint of the release group or encoder. While UPD is not as globally famous as groups like D-z0n3 or SPARKS, in niche Bollywood/high-codec circles, “UPD” often denotes:
: Advanced Audio Coding with 6-channel surround sound. jannat 2008 webrip 1080p 10bit hevc aac 51 x upd