The Loppunite, Gardevoirite, and Galladite are now available. I couldn't log in to the global link to get the code via Chrome though. Hadta use FireFox.
Via serebii:
"Details for the next Battle Competition have been announced. This is the Weakness Cup competition. This is a Double Battle competition using rules where only Pokémon with five or more weaknesses can be used. The standard Legendary Pokémon and Mythical Pokémon restrictions apply and you cannot use Ash Greninja. Only Weakness Policy and the type-reducing Berries such as Yache Berry can be used. Mega Stones are also not allowed. Registration runs from July 20th to July 27th. Battles will run from July 28th to July 30th. All entrants will get the Altarianite, Ampharosite, Latiosite and Latiasite Mega Stones."