MMY 7Up 7Down: the published rules
7Up 7Down is a two-dice total, and the whole game is a bet on which side of 7 the total lands.
The bet
Predict whether the sum of two dice will be above 7, below 7, or exactly 7. The developer calls the exact-7 outcome Lucky 7.
The roll
The dealer rolls two dice. A sum above 7 wins for 7Up, a sum below 7 wins for 7Down, and a sum of exactly 7 wins for the Lucky 7 bet.
What is not published
The odds attached to each outcome are not in the published description. Two dice have a fixed distribution, but the payout table is the app's, and it is not quoted here.
Where this comes from
The description on this page follows the text on mmy.com, the developer's site. Rule details that the developer does not publish are marked as not published, rather than filled in from other sites. Several MMY download sites state version numbers and file sizes that do not match the measured file; their game rules are not a safer source.
The game runs inside the MMY app, version 2.2.5, and there is no standalone download for it. Get the MMY APK
Other games in the same app
Playing it on a phone
The game runs inside the one MMY package, so the constraints are the package's. It needs Android 7.0 or newer and an arm64 handset, it installs as 19.98 MB, and the first launch downloads the game's assets over the network. A phone on a metered connection will spend that data once per fresh install. Later opens reuse what was fetched, until you clear the app's data.
Nothing on this page quotes a stake, a payout or a house edge. Where the developer publishes those they belong in the description above; where the developer does not, the table inside the app is the only place they appear, and they can change without this page knowing.