Casual abbreviation of アップデート, used mainly in informal speech, online, and among tech-savvy speakers.
See also: アップデート
The app update still hasn't finished.
I updated the game to the latest version.
最新のアプデでバグが直った。
The latest update fixed the bug.
明日、新しいアプデが来るらしい。
It seems a new update is coming out tomorrow.
The dev team released an emergency update.
The bug fix apparently has to wait for the next update.
Clipping of アップデート, from English 'update'.